1
|
Rastokina A, Cebrián J, Mozafari N, Mandel NH, Smith CI, Lopes M, Zain R, Mirkin S. Large-scale expansions of Friedreich's ataxia GAA•TTC repeats in an experimental human system: role of DNA replication and prevention by LNA-DNA oligonucleotides and PNA oligomers. Nucleic Acids Res 2023; 51:8532-8549. [PMID: 37216608 PMCID: PMC10484681 DOI: 10.1093/nar/gkad441] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 05/02/2023] [Accepted: 05/20/2023] [Indexed: 05/24/2023] Open
Abstract
Friedreich's ataxia (FRDA) is caused by expansions of GAA•TTC repeats in the first intron of the human FXN gene that occur during both intergenerational transmissions and in somatic cells. Here we describe an experimental system to analyze large-scale repeat expansions in cultured human cells. It employs a shuttle plasmid that can replicate from the SV40 origin in human cells or be stably maintained in S. cerevisiae utilizing ARS4-CEN6. It also contains a selectable cassette allowing us to detect repeat expansions that accumulated in human cells upon plasmid transformation into yeast. We indeed observed massive expansions of GAA•TTC repeats, making it the first genetically tractable experimental system to study large-scale repeat expansions in human cells. Further, GAA•TTC repeats stall replication fork progression, while the frequency of repeat expansions appears to depend on proteins implicated in replication fork stalling, reversal, and restart. Locked nucleic acid (LNA)-DNA mixmer oligonucleotides and peptide nucleic acid (PNA) oligomers, which interfere with triplex formation at GAA•TTC repeats in vitro, prevented the expansion of these repeats in human cells. We hypothesize, therefore, that triplex formation by GAA•TTC repeats stall replication fork progression, ultimately leading to repeat expansions during replication fork restart.
Collapse
Affiliation(s)
| | - Jorge Cebrián
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Negin Mozafari
- Department of Laboratory Medicine, Translational Research Center Karolinska (TRACK), Karolinska Institutet, Karolinska University Hospital, SE-171 77 Stockholm, Sweden
| | | | - C I Edvard Smith
- Department of Laboratory Medicine, Translational Research Center Karolinska (TRACK), Karolinska Institutet, Karolinska University Hospital, SE-171 77 Stockholm, Sweden
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland
| | - Rula Zain
- Department of Laboratory Medicine, Translational Research Center Karolinska (TRACK), Karolinska Institutet, Karolinska University Hospital, SE-171 77 Stockholm, Sweden
- Center for Rare Diseases, Karolinska University Hospital, SE-17176 Stockholm, Sweden
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02155, USA
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Li Y, Li J, Wang J, Zhang S, Giles K, Prakash TP, Rigo F, Napierala JS, Napierala M. Premature transcription termination at the expanded GAA repeats and aberrant alternative polyadenylation contributes to the Frataxin transcriptional deficit in Friedreich's ataxia. Hum Mol Genet 2022; 31:3539-3557. [PMID: 35708503 PMCID: PMC9558844 DOI: 10.1093/hmg/ddac134] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/12/2022] [Accepted: 06/05/2022] [Indexed: 11/18/2022] Open
Abstract
Frataxin deficiency in Friedreich's ataxia results from transcriptional downregulation of the FXN gene caused by expansion of the intronic trinucleotide guanine-adenine-adenine (GAA) repeats. We used multiple transcriptomic approaches to determine the molecular mechanism of transcription inhibition caused by long GAAs. We uncovered that transcription of FXN in patient cells is prematurely terminated upstream of the expanded repeats leading to the formation of a novel, truncated and stable RNA. This FXN early terminated transcript (FXN-ett) undergoes alternative, non-productive splicing and does not contribute to the synthesis of functional frataxin. The level the FXN-ett RNA directly correlates with the length of the longer of the two expanded GAA tracts. Targeting GAAs with antisense oligonucleotides or excision of the repeats eliminates the transcription impediment, diminishes expression of the aberrant FXN-ett, while increasing levels of FXN mRNA and frataxin. Non-productive transcription may represent a common phenomenon and attractive therapeutic target in diseases caused by repeat-mediated transcription aberrations.
Collapse
Affiliation(s)
- Yanjie Li
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA
| | - Jixue Li
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA
| | - Jun Wang
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA
| | - Siyuan Zhang
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA
| | - Keith Giles
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA
| | - Thazha P Prakash
- Ionis Pharmaceuticals Inc., 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Frank Rigo
- Ionis Pharmaceuticals Inc., 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Jill S Napierala
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA
- Department of Neurology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, USA
| | - Marek Napierala
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA
- Department of Neurology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, USA
| |
Collapse
|
4
|
Motley W, Chaudry V, Lloyd TE. Treatment and Management of Hereditary Neuropathies. Neuromuscul Disord 2022. [DOI: 10.1016/b978-0-323-71317-7.00014-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
5
|
Li Y, Li J, Wang J, Lynch D, Shen X, R. Corey D, Parekh D, Bhat B, Woo C, Cherry J, Napierala J, Napierala M. Targeting 3' and 5' untranslated regions with antisense oligonucleotides to stabilize frataxin mRNA and increase protein expression. Nucleic Acids Res 2021; 49:11560-11574. [PMID: 34718736 PMCID: PMC8599914 DOI: 10.1093/nar/gkab954] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 09/30/2021] [Accepted: 10/04/2021] [Indexed: 12/26/2022] Open
Abstract
Friedreich's ataxia (FRDA) is a severe multisystem disease caused by transcriptional repression induced by expanded GAA repeats located in intron 1 of the Frataxin (FXN) gene encoding frataxin. FRDA results from decreased levels of frataxin; thus, stabilization of the FXN mRNA already present in patient cells represents an attractive and unexplored therapeutic avenue. In this work, we pursued a novel approach based on oligonucleotide-mediated targeting of FXN mRNA ends to extend its half-life and availability as a template for translation. We demonstrated that oligonucleotides designed to bind to FXN 5' or 3' noncoding regions can increase FXN mRNA and protein levels. Simultaneous delivery of oligonucleotides targeting both ends increases efficacy of the treatment. The approach was confirmed in several FRDA fibroblast and induced pluripotent stem cell-derived neuronal progenitor lines. RNA sequencing and single-cell expression analyses confirmed oligonucleotide-mediated FXN mRNA upregulation. Mechanistically, a significant elongation of the FXN mRNA half-life without any changes in chromatin status at the FXN gene was observed upon treatment with end-targeting oligonucleotides, indicating that transcript stabilization is responsible for frataxin upregulation. These results identify a novel approach toward upregulation of steady-state mRNA levels via oligonucleotide-mediated end targeting that may be of significance to any condition resulting from transcription downregulation.
Collapse
Affiliation(s)
- Yanjie Li
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 1825 University Blvd, Birmingham, AL 35294, USA
| | - Jixue Li
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 1825 University Blvd, Birmingham, AL 35294, USA
| | - Jun Wang
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 1825 University Blvd, Birmingham, AL 35294, USA
| | - David R Lynch
- Division of Neurology and Pediatrics, Children’s Hospital of Philadelphia, Abramson Research Center, Room 502, Philadelphia, PA 19104, USA
| | - Xiulong Shen
- Department of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - David R. Corey
- Department of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Darshan Parekh
- Translate Bio, 29 Hartwell Avenue, Lexington, MA 02421, USA
| | | | - Caroline Woo
- Translate Bio, 29 Hartwell Avenue, Lexington, MA 02421, USA
| | | | - Jill S Napierala
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 1825 University Blvd, Birmingham, AL 35294, USA
| | - Marek Napierala
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, 1825 University Blvd, Birmingham, AL 35294, USA
| |
Collapse
|
6
|
Li J, Li Y, Wang J, Gonzalez TJ, Asokan A, Napierala JS, Napierala M. Defining Transcription Regulatory Elements in the Human Frataxin Gene: Implications for Gene Therapy. Hum Gene Ther 2020; 31:839-851. [PMID: 32527155 PMCID: PMC7462031 DOI: 10.1089/hum.2020.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/26/2020] [Indexed: 12/20/2022] Open
Abstract
Friedreich's ataxia (FRDA) is the most common inherited form of ataxia in humans. It is caused by severe downregulation of frataxin (FXN) expression instigated by hyperexpansion of the GAA repeats located in intron 1 of the FXN gene. Despite numerous studies focused on identifying compounds capable of stimulating FXN expression, current knowledge regarding cis-regulatory elements involved in FXN gene expression is lacking. Using a combination of episomal and genome-integrated constructs, we defined a minimal endogenous promoter sequence required to efficiently drive FXN expression in human cells. We generated 19 constructs varying in length of the DNA sequences upstream and downstream of the ATG start codon. Using transient transfection, we evaluated the capability of these constructs to drive FXN expression. These analyses allowed us to identify a region of the gene indispensable for FXN expression. Subsequently, selected constructs containing the FXN expression control regions of varying lengths were site specifically integrated into the genome of HEK293T and human-induced pluripotent stem cells (iPSCs). FXN expression was detected in iPSCs and persisted after differentiation to neuronal and cardiac cells, indicating lineage independent function of defined regulatory DNA sequences. Finally, based on these results, we generated AAV encoding miniFXN genes and demonstrated in vivo FXN expression in mice. Results of these studies identified FXN sequences necessary to express FXN in human and mouse cells and provided rationale for potential use of endogenous FXN sequence in gene therapy strategies for FRDA.
Collapse
Affiliation(s)
- Jixue Li
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Yanjie Li
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jun Wang
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Trevor J. Gonzalez
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Aravind Asokan
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Surgery, Duke University School of Medicine, Durham, North Carolina, USA
| | - Jill S. Napierala
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Marek Napierala
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama, USA
| |
Collapse
|
7
|
Ferreira GC, Oberstaller J, Fonseca R, Keller TE, Adapa SR, Gibbons J, Wang C, Liu X, Li C, Pham M, Dayhoff Ii GW, Duong LM, Reyes LT, Laratelli LE, Franz D, Fatumo S, Bari AG, Freischel A, Fiedler L, Dokur O, Sharma K, Cragun D, Busby B, Jiang RHY. Iron Hack - A symposium/hackathon focused on porphyrias, Friedreich's ataxia, and other rare iron-related diseases. F1000Res 2019; 8:1135. [PMID: 31824661 PMCID: PMC6894363 DOI: 10.12688/f1000research.19140.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/05/2019] [Indexed: 01/14/2023] Open
Abstract
Background: Basic and clinical scientific research at the University of South Florida (USF) have intersected to support a multi-faceted approach around a common focus on rare iron-related diseases. We proposed a modified version of the National Center for Biotechnology Information’s (NCBI) Hackathon-model to take full advantage of local expertise in building “Iron Hack”, a rare disease-focused hackathon. As the collaborative, problem-solving nature of hackathons tends to attract participants of highly-diverse backgrounds, organizers facilitated a symposium on rare iron-related diseases, specifically porphyrias and Friedreich’s ataxia, pitched at general audiences. Methods: The hackathon was structured to begin each day with presentations by expert clinicians, genetic counselors, researchers focused on molecular and cellular biology, public health/global health, genetics/genomics, computational biology, bioinformatics, biomolecular science, bioengineering, and computer science, as well as guest speakers from the American Porphyria Foundation (APF) and Friedreich’s Ataxia Research Alliance (FARA) to inform participants as to the human impact of these diseases. Results: As a result of this hackathon, we developed resources that are relevant not only to these specific disease-models, but also to other rare diseases and general bioinformatics problems. Within two and a half days, “Iron Hack” participants successfully built collaborative projects to visualize data, build databases, improve rare disease diagnosis, and study rare-disease inheritance. Conclusions: The purpose of this manuscript is to demonstrate the utility of a hackathon model to generate prototypes of generalizable tools for a given disease and train clinicians and data scientists to interact more effectively.
Collapse
Affiliation(s)
- Gloria C Ferreira
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, MDC 7, Tampa, FL, 33612, USA
| | - Jenna Oberstaller
- Global and Planetary Health, College of Public Health, University of South Florida, USF Genomics Program, 3720 Spectrum Blvd, Tampa, FL, 33612, USA
| | - Renée Fonseca
- Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, Tampa, FL, 33612, USA
| | - Thomas E Keller
- University of South Florida, USF Genomics Program, 3720 Spectrum Blvd, Tampa, FL, 33612, USA
| | - Swamy Rakesh Adapa
- Global and Planetary Health, College of Public Health, University of South Florida, USF Genomics Program, 3720 Spectrum Blvd, Tampa, FL, 33612, USA
| | - Justin Gibbons
- Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, Tampa, FL, 33612, USA
| | - Chengqi Wang
- Global and Planetary Health, College of Public Health, University of South Florida, USF Genomics Program, 3720 Spectrum Blvd, Tampa, FL, 33612, USA
| | - Xiaoming Liu
- Global and Planetary Health, College of Public Health, University of South Florida, USF Genomics Program, 3720 Spectrum Blvd, Tampa, FL, 33612, USA
| | - Chang Li
- Global and Planetary Health, College of Public Health, University of South Florida, USF Genomics Program, 3720 Spectrum Blvd, Tampa, FL, 33612, USA
| | - Minh Pham
- Center for Urban Transportation Research, University of South Florida, 4202 E. Fowler Avenue, CUT100, Tampa, FL, 33620, USA
| | - Guy W Dayhoff Ii
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, CHE 205, Tampa, FL, 33620-5250, USA
| | - Linh M Duong
- College of Public Health, University of South Florida, 13201 Bruce B. Downs Blvd., MDC 56, Tampa, FL, 33612, USA.,Moffitt Cancer Center, Tampa, FL, 33612, USA
| | - Luis Tañón Reyes
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, 4202 East Fowler Ave, ISA 2015 Tampa, FL, 33620, USA
| | - Luciano Enrique Laratelli
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, CHE 205, Tampa, FL, 33620-5250, USA
| | - Douglas Franz
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, CHE 205, Tampa, FL, 33620-5250, USA
| | - Segun Fatumo
- MRC/UVRI and LSHTM (Uganda Research Unit), Entebbe, Uganda
| | - Atm Golam Bari
- Department of Computer Science and Engineering, University of South Florida, Tampa, FL, USA
| | | | - Lindsey Fiedler
- College of Public Health, University of South Florida, 13201 Bruce B. Downs Blvd., MDC 56, Tampa, FL, 33612, USA
| | - Omkar Dokur
- Department of Computer Science and Engineering, University of South Florida, Tampa, FL, USA
| | | | - Deborah Cragun
- Global and Planetary Health, College of Public Health, University of South Florida, USF Genomics Program, 3720 Spectrum Blvd, Tampa, FL, 33612, USA
| | - Ben Busby
- National Library of Medicine, 8600 Rockville Pike, Bethesda, MD, 20894-6075, USA
| | - Rays H Y Jiang
- Global and Planetary Health, College of Public Health, University of South Florida, USF Genomics Program, 3720 Spectrum Blvd, Tampa, FL, 33612, USA
| |
Collapse
|
8
|
McGinty RJ, Puleo F, Aksenova AY, Hisey JA, Shishkin AA, Pearson EL, Wang ET, Housman DE, Moore C, Mirkin SM. A Defective mRNA Cleavage and Polyadenylation Complex Facilitates Expansions of Transcribed (GAA) n Repeats Associated with Friedreich's Ataxia. Cell Rep 2018; 20:2490-2500. [PMID: 28877480 DOI: 10.1016/j.celrep.2017.08.051] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/19/2017] [Accepted: 08/15/2017] [Indexed: 02/03/2023] Open
Abstract
Expansions of microsatellite repeats are responsible for numerous hereditary diseases in humans, including myotonic dystrophy and Friedreich's ataxia. Whereas the length of an expandable repeat is the main factor determining disease inheritance, recent data point to genomic trans modifiers that can impact the likelihood of expansions and disease progression. Detection of these modifiers may lead to understanding and treating repeat expansion diseases. Here, we describe a method for the rapid, genome-wide identification of trans modifiers for repeat expansion in a yeast experimental system. Using this method, we found that missense mutations in the endoribonuclease subunit (Ysh1) of the mRNA cleavage and polyadenylation complex dramatically increase the rate of (GAA)n repeat expansions but only when they are actively transcribed. These expansions correlate with slower transcription elongation caused by the ysh1 mutation. These results reveal an interplay between RNA processing and repeat-mediated genome instability, confirming the validity of our approach.
Collapse
Affiliation(s)
- Ryan J McGinty
- Department of Biology, Tufts University, Medford, MA 02421, USA
| | - Franco Puleo
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Anna Y Aksenova
- Department of Biology, Tufts University, Medford, MA 02421, USA; Laboratory of Amyloid Biology, St. Petersburg State University, St. Petersburg 199034, Russia
| | - Julia A Hisey
- Department of Biology, Tufts University, Medford, MA 02421, USA
| | - Alexander A Shishkin
- Department of Biology, Tufts University, Medford, MA 02421, USA; The Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA
| | - Erika L Pearson
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Eric T Wang
- The David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA 02139, USA; Center for Neurogenetics, University of Florida, Gainesville, FL 32610, USA
| | - David E Housman
- The David H. Koch Institute for Integrative Cancer Research at MIT, Cambridge, MA 02139, USA
| | - Claire Moore
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02421, USA.
| |
Collapse
|
9
|
Polak U, Li Y, Butler JS, Napierala M. Alleviating GAA Repeat Induced Transcriptional Silencing of the Friedreich's Ataxia Gene During Somatic Cell Reprogramming. Stem Cells Dev 2016; 25:1788-1800. [PMID: 27615158 PMCID: PMC5155629 DOI: 10.1089/scd.2016.0147] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/09/2016] [Indexed: 12/13/2022] Open
Abstract
Friedreich's ataxia (FRDA) is the most common autosomal recessive ataxia. This severe neurodegenerative disease is caused by an expansion of guanine-adenine-adenine (GAA) repeats located in the first intron of the frataxin (FXN) gene, which represses its transcription. Although transcriptional silencing is associated with heterochromatin-like changes in the vicinity of the expanded GAAs, the exact mechanism and pathways involved in transcriptional inhibition are largely unknown. As major remodeling of the epigenome is associated with somatic cell reprogramming, modulating chromatin modification pathways during the cellular transition from a somatic to a pluripotent state is likely to generate permanent changes to the epigenetic landscape. We hypothesize that the epigenetic modifications in the vicinity of the GAA repeats can be reversed by pharmacological modulation during somatic cell reprogramming. We reprogrammed FRDA fibroblasts into induced pluripotent stem cells (iPSCs) in the presence of various small molecules that target DNA methylation and histone acetylation and methylation. Treatment of FRDA iPSCs with two compounds, sodium butyrate (NaB) and Parnate, led to an increase in FXN expression and correction of repressive marks at the FXN locus, which persisted for several passages. However, prolonged culture of the epigenetically modified FRDA iPSCs led to progressive expansions of the GAA repeats and a corresponding decrease in FXN expression. Furthermore, we uncovered that differentiation of these iPSCs into neurons also results in resilencing of the FXN gene. Taken together, these results demonstrate that transcriptional repression caused by long GAA repeat tracts can be partially or transiently reversed by altering particular epigenetic modifications, thus revealing possibilities for detailed analyses of silencing mechanism and development of new therapeutic approaches for FRDA.
Collapse
Affiliation(s)
- Urszula Polak
- Department of Molecular Carcinogenesis, Center for Cancer Epigenetics, University of Texas MD Anderson Cancer Center, Smithville, Texas
| | - Yanjie Li
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, Birmingham, Alabama
| | - Jill Sergesketter Butler
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, Birmingham, Alabama
| | - Marek Napierala
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, Birmingham, Alabama
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| |
Collapse
|
10
|
Jaworska E, Kozlowska E, Switonski PM, Krzyzosiak WJ. Modeling simple repeat expansion diseases with iPSC technology. Cell Mol Life Sci 2016; 73:4085-100. [PMID: 27261369 PMCID: PMC11108530 DOI: 10.1007/s00018-016-2284-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 05/20/2016] [Accepted: 05/24/2016] [Indexed: 12/20/2022]
Abstract
A number of human genetic disorders, including Huntington's disease, myotonic dystrophy type 1, C9ORF72 form of amyotrophic lateral sclerosis and several spinocerebellar ataxias, are caused by the expansion of various microsatellite sequences in single implicated genes. The neurodegenerative and neuromuscular nature of the repeat expansion disorders considerably limits the access of researchers to appropriate cellular models of these diseases. This limitation, however, can be overcome by the application of induced pluripotent stem cell (iPSC) technology. In this paper, we review the current knowledge on the modeling of repeat expansion diseases with human iPSCs and iPSC-derived cells, focusing on the disease phenotypes recapitulated in these models. In subsequent sections, we provide basic practical knowledge regarding iPSC generation, characterization and differentiation into neurons. We also cover disease modeling in iPSCs, neuronal stem cells and specialized neuronal cultures. Furthermore, we also summarize the therapeutic potential of iPSC technology in repeat expansion diseases.
Collapse
Affiliation(s)
- Edyta Jaworska
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704, Poznan, Poland
| | - Emilia Kozlowska
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704, Poznan, Poland
| | - Pawel M Switonski
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704, Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704, Poznan, Poland.
| |
Collapse
|
11
|
Abstract
Transcription termination is a fundamental process in which RNA polymerase ceases RNA chain extension and dissociates from the chromatin template, thereby defining the end of the transcription unit. Our understanding of the biological role and functional importance of termination by RNA polymerase II and the range of processes in which it is involved has grown significantly in recent years. A large set of nucleic acid-binding proteins and enzymes have been identified as part of the termination machinery. A greater appreciation for the coupling of termination to RNA processing and metabolism has been recognized. In addition to serving as an essential step at the end of the transcription cycle, termination is involved in the regulation of a broad range of cellular processes. More recently, a role for termination in pervasive transcription, non-coding RNA regulation, genetic stability, chromatin remodeling, the immune response, and disease has come to the fore. Interesting mechanistic questions remain, but the last several years have resulted in significant insights into termination and an increasing recognition of its biological importance.
Collapse
Affiliation(s)
- Travis J Loya
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Daniel Reines
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322, USA
| |
Collapse
|
12
|
Chatterjee N, Lin Y, Wilson JH. Mismatch repair enhances convergent transcription-induced cell death at trinucleotide repeats by activating ATR. DNA Repair (Amst) 2016; 42:26-32. [PMID: 27131875 DOI: 10.1016/j.dnarep.2016.03.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 03/15/2016] [Accepted: 03/16/2016] [Indexed: 01/08/2023]
Abstract
Trinucleotide repeat (TNR) expansion beyond a certain threshold results in some 20 incurable neurodegenerative disorders where disease anticipation positively correlates with repeat length. Long TNRs typically display a bias toward further expansion during germinal transmission from parents to offspring, and then are highly unstable in somatic tissues of affected individuals. Understanding mechanisms of TNR instability will provide insights into disease pathogenesis. Previously, we showed that enhanced convergent transcription at long CAG repeat tracks induces TNR instability and cell death via ATR activation. Components of TC-NER (transcription-coupled nucleotide excision repair) and RNaseH enzymes that resolve RNA/DNA hybrids oppose cell death, whereas the MSH2 component of MMR (mismatch repair) enhances cell death. The exact role of the MMR pathway during convergent transcription-induced cell death at CAG repeats is not well understood. In this study, we show that siRNA knockdowns of MMR components-MSH2, MSH3, MLHI, PMS2, and PCNA-reduce DNA toxicity. Furthermore, knockdown of MSH2, MLH1, and PMS2 significantly reduces the frequency of ATR foci formation. These observations suggest that MMR proteins activate DNA toxicity by modulating ATR foci formation during convergent transcription.
Collapse
Affiliation(s)
- Nimrat Chatterjee
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Yunfu Lin
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - John H Wilson
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| |
Collapse
|
13
|
Li L, Matsui M, Corey DR. Activating frataxin expression by repeat-targeted nucleic acids. Nat Commun 2016; 7:10606. [PMID: 26842135 PMCID: PMC4742999 DOI: 10.1038/ncomms10606] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 01/04/2016] [Indexed: 12/20/2022] Open
Abstract
Friedreich's ataxia is an incurable genetic disorder caused by a mutant expansion of the trinucleotide GAA within an intronic FXN RNA. This expansion leads to reduced expression of frataxin (FXN) protein and evidence suggests that transcriptional repression is caused by an R-loop that forms between the expanded repeat RNA and complementary genomic DNA. Synthetic agents that increase levels of FXN protein might alleviate the disease. We demonstrate that introducing anti-GAA duplex RNAs or single-stranded locked nucleic acids into patient-derived cells increases FXN protein expression to levels similar to analogous wild-type cells. Our data are significant because synthetic nucleic acids that target GAA repeats can be lead compounds for restoring curative FXN levels. More broadly, our results demonstrate that interfering with R-loop formation can trigger gene activation and reveal a new strategy for upregulating gene expression.
Collapse
Affiliation(s)
- Liande Li
- Departments of Pharmacology and Biochemistry, UT Southwestern Medical Center at Dallas, 6001 Forest Park Road, Dallas, Texas 75390-9041, USA
| | - Masayuki Matsui
- Departments of Pharmacology and Biochemistry, UT Southwestern Medical Center at Dallas, 6001 Forest Park Road, Dallas, Texas 75390-9041, USA
| | - David R. Corey
- Departments of Pharmacology and Biochemistry, UT Southwestern Medical Center at Dallas, 6001 Forest Park Road, Dallas, Texas 75390-9041, USA
| |
Collapse
|
14
|
Mellor J, Woloszczuk R, Howe FS. The Interleaved Genome. Trends Genet 2016; 32:57-71. [DOI: 10.1016/j.tig.2015.10.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 09/29/2015] [Accepted: 10/23/2015] [Indexed: 12/25/2022]
|
15
|
Li Y, Lu Y, Polak U, Lin K, Shen J, Farmer J, Seyer L, Bhalla AD, Rozwadowska N, Lynch DR, Butler JS, Napierala M. Expanded GAA repeats impede transcription elongation through the FXN gene and induce transcriptional silencing that is restricted to the FXN locus. Hum Mol Genet 2015; 24:6932-43. [PMID: 26401053 PMCID: PMC4654050 DOI: 10.1093/hmg/ddv397] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 09/21/2015] [Indexed: 11/13/2022] Open
Abstract
Friedreich's ataxia (FRDA) is a severe neurodegenerative disease caused by homozygous expansion of the guanine-adenine-adenine (GAA) repeats in intron 1 of the FXN gene leading to transcriptional repression of frataxin expression. Post-translational histone modifications that typify heterochromatin are enriched in the vicinity of the repeats, whereas active chromatin marks in this region are underrepresented in FRDA samples. Yet, the immediate effect of the expanded repeats on transcription progression through FXN and their long-range effect on the surrounding genomic context are two critical questions that remain unanswered in the molecular pathogenesis of FRDA. To address these questions, we conducted next-generation RNA sequencing of a large cohort of FRDA and control primary fibroblasts. This comprehensive analysis revealed that the GAA-induced silencing effect does not influence expression of neighboring genes upstream or downstream of FXN. Furthermore, no long-range silencing effects were detected across a large portion of chromosome 9. Additionally, results of chromatin immunoprecipitation studies confirmed that histone modifications associated with repressed transcription are confined to the FXN locus. Finally, deep sequencing of FXN pre-mRNA molecules revealed a pronounced defect in the transcription elongation rate in FRDA cells when compared with controls. These results indicate that approaches aimed to reactivate frataxin expression should simultaneously address deficits in transcription initiation and elongation at the FXN locus.
Collapse
Affiliation(s)
- Yanjie Li
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA
| | - Yue Lu
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, USA
| | - Urszula Polak
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, USA, Department of Cell Biology, Poznan University of Medical Sciences, Rokietnicka 5D, Poznan 60-806, Poland
| | - Kevin Lin
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, USA
| | - Jianjun Shen
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, USA
| | - Jennifer Farmer
- Division of Neurology and Pediatrics, Children's Hospital of Philadelphia, Abramson Research Center Room 502, Philadelphia, PA 19104, USA
| | - Lauren Seyer
- Division of Neurology and Pediatrics, Children's Hospital of Philadelphia, Abramson Research Center Room 502, Philadelphia, PA 19104, USA
| | - Angela D Bhalla
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA
| | - Natalia Rozwadowska
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA, Institute of Human Genetics, Polish Academy of Science, Strzeszynska 32, Poznan 60-479, Poland
| | - David R Lynch
- Division of Neurology and Pediatrics, Children's Hospital of Philadelphia, Abramson Research Center Room 502, Philadelphia, PA 19104, USA
| | - Jill Sergesketter Butler
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA,
| | - Marek Napierala
- Department of Biochemistry and Molecular Genetics, UAB Stem Cell Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL 35294, USA, Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan 61-704, Poland and
| |
Collapse
|
16
|
Gerhardt J. Epigenetic modifications in human fragile X pluripotent stem cells; Implications in fragile X syndrome modeling. Brain Res 2015; 1656:55-62. [PMID: 26475977 DOI: 10.1016/j.brainres.2015.10.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 08/18/2015] [Accepted: 10/02/2015] [Indexed: 12/18/2022]
Abstract
Patients with fragile X syndrome (FXS) exhibit moderate to severe intellectual disabilities. In addition, one-third of FXS patients show characteristics of autism spectrum disorder. FXS is caused by a trinucleotide repeat expansion, which leads to silencing of the fragile X mental retardation (FMR1) gene. The absence of the FMR1 gene product, FMRP, is the reason for the disease symptoms. It has been suggested that repeat instability and transcription of the FMR1 gene occur during early embryonic development, while after cell differentiation repeats become stable and the FMR1 gene is silent. Epigenetic marks, such as DNA methylation, are associated with gene silencing and repeat stability at the FMR1 locus. However, the mechanisms leading to gene silencing and repeat expansion are still ambiguous, because studies at the human genomic locus were limited until now. The FXS pluripotent stem cells, recently derived from FXS adult cells and FXS blastocysts, are new useful tools to examine these mechanisms at the human endogenous FMR1 locus. This review summarizes the epigenetic features and experimental studies of FXS human embryonic and FXS induced pluripotent stem cells, generated so far. This article is part of a Special Issue entitled SI: Exploiting human neurons.
Collapse
Affiliation(s)
- Jeannine Gerhardt
- Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx 10461, USA.
| |
Collapse
|