1
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Wu Y, Song T, Xu Q. R-LOOPs on Short Tandem Repeat Expansion Disorders in Neurodegenerative Diseases. Mol Neurobiol 2023; 60:7185-7195. [PMID: 37540313 DOI: 10.1007/s12035-023-03531-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 07/24/2023] [Indexed: 08/05/2023]
Abstract
Expansions of short tandem repeats (STRs) have been found to be present in more than 50 diseases and have a close connection with neurodegenerative diseases. Transcriptional silencing and R-LOOP formation, RNA-mediated sequestration of RNA-binding proteins (RBPs), gain-of-function (GOF) proteins containing expanded repeats, and repeat-associated non-AUG (RAN) translation of toxic repeat peptides are some potential molecular mechanisms underlying STR expansion disorders. R-LOOP, a byproduct of transcription, is a three-stranded nucleic acid structure with abnormal accumulation that participates in the pathogenesis of STR expansion disorders by inducing DNA damage and genome instability. R-LOOPs can engender a series of DNA damage, such as DNA double-strand breaks (DSBs), single-strand breaks (SSBs), DNA recombination, or mutations in the DNA replication, transcription, or repair processes. In this review, we provide an in-depth discussion of recent advancements in R-LOOP and systematically elaborate on its genetic destabilizing effects in several neurodegenerative diseases. These molecular mechanisms will provide novel targets for drug design and therapeutic upgrading of these devastating diseases.
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Affiliation(s)
- Yiting Wu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Tingwei Song
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Qian Xu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Changsha, China.
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China.
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2
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Gambelli A, Ferrando A, Boncristiani C, Schoeftner S. Regulation and function of R-loops at repetitive elements. Biochimie 2023; 214:141-155. [PMID: 37619810 DOI: 10.1016/j.biochi.2023.08.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/13/2023] [Accepted: 08/19/2023] [Indexed: 08/26/2023]
Abstract
R-loops are atypical, three-stranded nucleic acid structures that contain a stretch of RNA:DNA hybrids and an unpaired, single stranded DNA loop. R-loops are physiological relevant and can act as regulators of gene expression, chromatin structure, DNA damage repair and DNA replication. However, unscheduled and persistent R-loops are mutagenic and can mediate replication-transcription conflicts, leading to DNA damage and genome instability if left unchecked. Detailed transcriptome analysis unveiled that 85% of the human genome, including repetitive regions, hold transcriptional activity. This anticipates that R-loops management plays a central role for the regulation and integrity of genomes. This function is expected to have a particular relevance for repetitive sequences that make up to 75% of the human genome. Here, we review the impact of R-loops on the function and stability of repetitive regions such as centromeres, telomeres, rDNA arrays, transposable elements and triplet repeat expansions and discuss their relevance for associated pathological conditions.
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Affiliation(s)
- Alice Gambelli
- Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy
| | - Alessandro Ferrando
- Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy
| | - Chiara Boncristiani
- Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy
| | - Stefan Schoeftner
- Dipartimento di Scienze della Vita, Università degli Studi di Trieste, Via E. Weiss 2, 34127, Trieste, Italy.
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3
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Cuartas J, Gangwani L. R-loop Mediated DNA Damage and Impaired DNA Repair in Spinal Muscular Atrophy. Front Cell Neurosci 2022; 16:826608. [PMID: 35783101 PMCID: PMC9243258 DOI: 10.3389/fncel.2022.826608] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 05/23/2022] [Indexed: 12/02/2022] Open
Abstract
Defects in DNA repair pathways are a major cause of DNA damage accumulation leading to genomic instability and neurodegeneration. Efficient DNA damage repair is critical to maintain genomicstability and support cell function and viability. DNA damage results in the activation of cell death pathways, causing neuronal death in an expanding spectrum of neurological disorders, such as amyotrophic lateral sclerosis (ALS), Parkinson’s disease (PD), Alzheimer’s disease (AD), and spinal muscular atrophy (SMA). SMA is a neurodegenerative disorder caused by mutations in the Survival Motor Neuron 1 (SMN1) gene. SMA is characterized by the degeneration of spinal cord motor neurons due to low levels of the SMN protein. The molecular mechanism of selective motor neuron degeneration in SMA was unclear for about 20 years. However, several studies have identified biochemical and molecular mechanisms that may contribute to the predominant degeneration of motor neurons in SMA, including the RhoA/ROCK, the c-Jun NH2-terminal kinase (JNK), and p53-mediated pathways, which are involved in mediating DNA damage-dependent cell death. Recent studies provided insight into selective degeneration of motor neurons, which might be caused by accumulation of R-loop-mediated DNA damage and impaired non-homologous end joining (NHEJ) DNA repair pathway leading to genomic instability. Here, we review the latest findings involving R-loop-mediated DNA damage and defects in neuron-specific DNA repair mechanisms in SMA and discuss these findings in the context of other neurodegenerative disorders linked to DNA damage.
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Affiliation(s)
- Juliana Cuartas
- Center of Emphasis in Neurosciences, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
| | - Laxman Gangwani
- Center of Emphasis in Neurosciences, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
- Francis Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
- *Correspondence: Laxman Gangwani
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4
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Cobos S, Torrente MP. Epidrugs in Amyotrophic Lateral Sclerosis/Frontotemporal Dementia: Contextualizing a Role for Histone Kinase Inhibition in Neurodegenerative Disease. ACS Pharmacol Transl Sci 2022; 5:134-137. [PMID: 35187420 PMCID: PMC8844958 DOI: 10.1021/acsptsci.1c00265] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Indexed: 01/23/2023]
Abstract
Breakthroughs in understanding the epigenetic mechanisms involved in neurodegenerative disease have highlighted "epidrugs" as a potential avenue for therapeutic development. Here, we expand on the future of epidrugs against neurodegeneration and discuss promising novel targets underexploited thus far: histone kinases.
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Affiliation(s)
- Samantha
N. Cobos
- Chemistry
Department of Brooklyn College, Brooklyn, New York 11210, United States,Ph.D.
Program in Chemistry, The Graduate Center
of the City University of New York, New York, New York 10016, United States
| | - Mariana P. Torrente
- Chemistry
Department of Brooklyn College, Brooklyn, New York 11210, United States,Ph.D.
Program in Chemistry, The Graduate Center
of the City University of New York, New York, New York 10016, United States,Ph.D.
Program in Biochemistry, The Graduate Center
of the City University of New York, New York, New York 10016, United States,Ph.D.
Program in Biology, The Graduate Center
of the City University of New York, New York, New York 10016, United States,
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5
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Xu J, Huang H, Zhou X. G-Quadruplexes in Neurobiology and Virology: Functional Roles and Potential Therapeutic Approaches. JACS AU 2021; 1:2146-2161. [PMID: 34977886 PMCID: PMC8715485 DOI: 10.1021/jacsau.1c00451] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Indexed: 05/11/2023]
Abstract
A G-quadruplex (G4) is a four-stranded nucleic acid secondary structure maintained by Hoogsteen hydrogen bonds established between four guanines. Experimental studies and bioinformatics predictions support the hypothesis that these structures are involved in different cellular functions associated with both DNA and RNA processes. An increasing number of diseases have been shown to be associated with abnormal G4 regulation. Here, we describe the existence of G4 and then discuss G4-related pathogenic mechanisms in neurodegenerative diseases and the viral life cycle. Furthermore, we focus on the role of G4s in the design of antiviral therapy and neuropharmacology, including G4 ligands, G4-based aptamers, G4-related proteins, and CRISPR-based sequence editing, along with a discussion of limitations and insights into the prospects of this unusual nucleic acid secondary structure in therapeutics. Finally, we highlight progress and challenges in this field and the potential G4-related research fields.
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Affiliation(s)
- Jinglei Xu
- The
Institute of Advanced Studies, Key Laboratory of Biomedical Polymers-Ministry
of Education, Wuhan University, Wuhan 430072, China
| | - Haiyan Huang
- Key
Laboratory of Biomedical Polymers-Ministry of Education, College of
Chemistry and Molecular Sciences, Wuhan
University, Wuhan 430072, China
| | - Xiang Zhou
- The
Institute of Advanced Studies, Key Laboratory of Biomedical Polymers-Ministry
of Education, Wuhan University, Wuhan 430072, China
- Key
Laboratory of Biomedical Polymers-Ministry of Education, College of
Chemistry and Molecular Sciences, Wuhan
University, Wuhan 430072, China
- Email to X.Z.:
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6
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Wang E, Thombre R, Shah Y, Latanich R, Wang J. G-Quadruplexes as pathogenic drivers in neurodegenerative disorders. Nucleic Acids Res 2021; 49:4816-4830. [PMID: 33784396 PMCID: PMC8136783 DOI: 10.1093/nar/gkab164] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 02/20/2021] [Accepted: 03/29/2021] [Indexed: 12/12/2022] Open
Abstract
G-quadruplexes (G4s), higher-order DNA and RNA secondary structures featuring guanine-rich nucleic acid sequences with various conformations, are widely distributed in the human genome. These structural motifs are known to participate in basic cellular processes, including transcription, splicing, and translation, and their functions related to health and disease are becoming increasingly recognized. In this review, we summarize the landscape of G4s involved in major neurodegenerative disorders, describing the genes that contain G4-forming sequences and proteins that have high affinity for G4-containing elements. The functions of G4s are diverse, with potentially protective or deleterious effects in the pathogenic cascades of various neurological diseases. While the studies of the functions of G4s in vivo, including those involved in pathophysiology, are still in their early stages, we will nevertheless discuss the evidence pointing to their biological relevance. A better understanding of this unique structural element in the biological context is important for unveiling its potential roles in the pathogenesis of diseases such as neurodegeneration and for designing new diagnostic and therapeutic strategies.
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Affiliation(s)
- Ernest Wang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore MD, 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Ravi Thombre
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore MD, 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Yajas Shah
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore MD, 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Rachel Latanich
- Department of Medicine, Division of Gastroenterology and Hepatology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Jiou Wang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore MD, 21205, USA.,Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
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7
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Lee JH, Ryu SW, Ender NA, Paull TT. Poly-ADP-ribosylation drives loss of protein homeostasis in ATM and Mre11 deficiency. Mol Cell 2021; 81:1515-1533.e5. [PMID: 33571423 PMCID: PMC8026623 DOI: 10.1016/j.molcel.2021.01.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 12/14/2020] [Accepted: 01/19/2021] [Indexed: 12/11/2022]
Abstract
Loss of the ataxia-telangiectasia mutated (ATM) kinase causes cerebellum-specific neurodegeneration in humans. We previously demonstrated that deficiency in ATM activation via oxidative stress generates insoluble protein aggregates in human cells, reminiscent of protein dysfunction in common neurodegenerative disorders. Here, we show that this process is driven by poly-ADP-ribose polymerases (PARPs) and that the insoluble protein species arise from intrinsically disordered proteins associating with PAR-associated genomic sites in ATM-deficient cells. The lesions implicated in this process are single-strand DNA breaks dependent on reactive oxygen species, transcription, and R-loops. Human cells expressing Mre11 A-T-like disorder mutants also show PARP-dependent aggregation identical to ATM deficiency. Lastly, analysis of A-T patient cerebellum samples shows widespread protein aggregation as well as loss of proteins known to be critical in human spinocerebellar ataxias that is not observed in neocortex tissues. These results provide a hypothesis accounting for loss of protein integrity and cerebellum function in A-T.
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Affiliation(s)
- Ji-Hoon Lee
- The University of Texas at Austin, Department of Molecular Biosciences, Austin, TX 78712, USA
| | - Seung W Ryu
- The University of Texas at Austin, Department of Molecular Biosciences, Austin, TX 78712, USA
| | - Nicolette A Ender
- The University of Texas at Austin, Department of Molecular Biosciences, Austin, TX 78712, USA
| | - Tanya T Paull
- The University of Texas at Austin, Department of Molecular Biosciences, Austin, TX 78712, USA.
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8
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Exploration of head-to-tail and head-to-head isomers of a guanine quadruplex platinum-based binder. Inorganica Chim Acta 2021. [DOI: 10.1016/j.ica.2020.120236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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Miron CE, Staalduinen L, Rangaswamy AM, Chen M, Liang Y, Jia Z, Mergny J, Petitjean A. Going Platinum to the Tune of a Remarkable Guanine Quadruplex Binder: Solution‐ and Solid‐State Investigations. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202012520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Caitlin E. Miron
- Department of Chemistry Queen's University 90 Bader Lane Kingston ON K7L 3N6 Canada
| | - Laura Staalduinen
- Department of Biomedical and Molecular Sciences Queen's University Kingston ON K7L 3N6 Canada
| | - Alana M. Rangaswamy
- Department of Chemistry Queen's University 90 Bader Lane Kingston ON K7L 3N6 Canada
| | - Mickey Chen
- Department of Chemistry Queen's University 90 Bader Lane Kingston ON K7L 3N6 Canada
| | - Yushi Liang
- Department of Chemistry Queen's University 90 Bader Lane Kingston ON K7L 3N6 Canada
| | - Zongchao Jia
- Department of Biomedical and Molecular Sciences Queen's University Kingston ON K7L 3N6 Canada
| | - Jean‐Louis Mergny
- Inserm U1212/CNRS UMR5320/Université de Bordeaux Institut Européen de Chimie et Biologie 2 rue Escarpit 33607 Pessac France
- Laboratoire d'Optique et Biosciences École Polytechnique CNRS INSERM Institut Polytechnique de Paris 91128 Palaiseau cedex France
| | - Anne Petitjean
- Department of Chemistry Queen's University 90 Bader Lane Kingston ON K7L 3N6 Canada
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10
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Miron CE, van Staalduinen L, Rangaswamy AM, Chen M, Liang Y, Jia Z, Mergny JL, Petitjean A. Going Platinum to the Tune of a Remarkable Guanine Quadruplex Binder: Solution- and Solid-State Investigations. Angew Chem Int Ed Engl 2020; 60:2500-2507. [PMID: 33090592 DOI: 10.1002/anie.202012520] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Indexed: 12/17/2022]
Abstract
Guanine quadruplex recognition has gained increasing attention, inspired by the growing awareness of the key roles played by these non-canonical nucleic acid architectures in cellular regulatory processes. We report here the solution and solid-state studies of a novel planar platinum(II) complex that is easily assembled from a simple ligand, and exhibits notable binding affinity for guanine quadruplex structures, while maintaining good selectivity for guanine quadruplex over duplex structures. A crystal structure of this ligand complexed with a telomeric quadruplex confirms double end-capping, with dimerization at the 5' interface.
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Affiliation(s)
- Caitlin E Miron
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, ON, K7L 3N6, Canada
| | - Laura van Staalduinen
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Alana M Rangaswamy
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, ON, K7L 3N6, Canada
| | - Mickey Chen
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, ON, K7L 3N6, Canada
| | - Yushi Liang
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, ON, K7L 3N6, Canada
| | - Zongchao Jia
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Jean-Louis Mergny
- Inserm U1212/CNRS UMR5320/Université de Bordeaux, Institut Européen de Chimie et Biologie, 2 rue Escarpit, 33607, Pessac, France.,Laboratoire d'Optique et Biosciences, École Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91128, Palaiseau cedex, France
| | - Anne Petitjean
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, ON, K7L 3N6, Canada
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11
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Lu Y, Dohno C, Nakatani K. Recognition of expanded GGGGCC hexanucleotide repeat by synthetic ligand through interhelical binding. Biochem Biophys Res Commun 2020; 531:56-61. [DOI: 10.1016/j.bbrc.2020.03.107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/26/2020] [Accepted: 03/19/2020] [Indexed: 12/14/2022]
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12
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Yan Q, Shields EJ, Bonasio R, Sarma K. Mapping Native R-Loops Genome-wide Using a Targeted Nuclease Approach. Cell Rep 2020; 29:1369-1380.e5. [PMID: 31665646 PMCID: PMC6870988 DOI: 10.1016/j.celrep.2019.09.052] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 09/06/2019] [Accepted: 09/18/2019] [Indexed: 12/20/2022] Open
Abstract
R-loops are three-stranded DNA:RNA hybrids that are implicated in many nuclear processes. While R-loops may have physiological roles, the formation of stable, aberrant R-loops has been observed in neurological disorders and cancers. Current methods to assess their genome-wide distribution rely on affinity purification, which is plagued by large input requirements, high noise, and poor sensitivity for dynamic R-loops. Here, we present MapR, a method that utilizes RNase H to guide micrococcal nuclease to R-loops, which are subsequently cleaved, released, and identified by sequencing. MapR detects R-loops formed at promoters and active enhancers that are likely to form transient R-loops due to the low transcriptional output of these regulatory elements and the short-lived nature of enhancer RNAs. MapR is as specific as existing techniques and more sensitive, allowing for genomewide coverage with low input material in a fraction of the time. Yan et al. report a fast, easy, antibodyindependent strategy, MapR, to identify native R-loops in vivo without the need for generating stable cell lines. MapR uses the natural affinity and specificity of RNase H to detect R-loops. MapR identifies dynamic R-loops formed at enhancers with high sensitivity.
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Affiliation(s)
- Qingqing Yan
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, PA 19104, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Emily J Shields
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Graduate Group in Genomics and Computational Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Roberto Bonasio
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Kavitha Sarma
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, PA 19104, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA 19104, USA.
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13
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Abstract
R loops are transient three-stranded nucleic acid structures that form physiologically during transcription when a nascent RNA transcript hybridizes with the DNA template strand, leaving a single strand of displaced nontemplate DNA. However, aberrant persistence of R-loops can cause DNA damage by inducing genomic instability. Indeed, evidence has emerged that R-loops might represent a key element in the pathogenesis of human diseases, including cancer, neurodegeneration, and motor neuron disorders. Mutations in genes directly involved in R-loop biology, such as SETX (senataxin), or unstable DNA expansion eliciting R-loop generation, such as C9ORF72 HRE, can cause DNA damage and ultimately result in motor neuron cell death. In this review, we discuss current advancements in this field with a specific focus on motor neuron diseases associated with deregulation of R-loop structures. These mechanisms can represent novel therapeutic targets for these devastating, incurable diseases.
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14
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Tang SS, Li J, Tan L, Yu JT. Genetics of Frontotemporal Lobar Degeneration: From the Bench to the Clinic. J Alzheimers Dis 2017; 52:1157-76. [PMID: 27104909 DOI: 10.3233/jad-160236] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Frontotemporal lobar degeneration (FTLD) is a clinically heterogeneous neurodegenerative disease with a strong genetic component. In this review, we summarize most common mutations in MAPT, GRN, and C90RF72, as well as less common mutations in VCP, CHMP2B, TARDBP, FUS gene and so on. Several guidelines have been developed to help gene testing based on genotype-phenotype correlation, the underlying histopathological subtypes, and the neuroanatomic associations. Furthermore, we also summarize molecular pathways implicated by genes and novel targets for FTLD prevention and management in recent years.
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15
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Cammas A, Millevoi S. RNA G-quadruplexes: emerging mechanisms in disease. Nucleic Acids Res 2017; 45:1584-1595. [PMID: 28013268 PMCID: PMC5389700 DOI: 10.1093/nar/gkw1280] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 12/16/2016] [Indexed: 12/13/2022] Open
Abstract
RNA G-quadruplexes (G4s) are formed by G-rich RNA sequences in protein-coding (mRNA) and non-coding (ncRNA) transcripts that fold into a four-stranded conformation. Experimental studies and bioinformatic predictions support the view that these structures are involved in different cellular functions associated to both DNA processes (telomere elongation, recombination and transcription) and RNA post-transcriptional mechanisms (including pre-mRNA processing, mRNA turnover, targeting and translation). An increasing number of different diseases have been associated with the inappropriate regulation of RNA G4s exemplifying the potential importance of these structures on human health. Here, we review the different molecular mechanisms underlying the link between RNA G4s and human diseases by proposing several overlapping models of deregulation emerging from recent research, including (i) sequestration of RNA-binding proteins, (ii) aberrant expression or localization of RNA G4-binding proteins, (iii) repeat associated non-AUG (RAN) translation, (iv) mRNA translational blockade and (v) disabling of protein–RNA G4 complexes. This review also provides a comprehensive survey of the functional RNA G4 and their mechanisms of action. Finally, we highlight future directions for research aimed at improving our understanding on RNA G4-mediated regulatory mechanisms linked to diseases.
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Affiliation(s)
- Anne Cammas
- Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III-Paul Sabatier, Inserm, CRCT, Toulouse, France
| | - Stefania Millevoi
- Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III-Paul Sabatier, Inserm, CRCT, Toulouse, France
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16
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A C9ORF72 BAC mouse model recapitulates key epigenetic perturbations of ALS/FTD. Mol Neurodegener 2017; 12:46. [PMID: 28606110 PMCID: PMC5468954 DOI: 10.1186/s13024-017-0185-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 05/30/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Amyotrophic Lateral Sclerosis (ALS) is a fatal and progressive neurodegenerative disorder with identified genetic causes representing a significant minority of all cases. A GGGGCC hexanucleotide repeat expansion (HRE) mutation within the C9ORF72 gene has recently been identified as the most frequent known cause of ALS. The expansion leads to partial heterochromatinization of the locus, yet mutant RNAs and dipeptide repeat proteins (DPRs) are still produced in sufficient quantities to confer neurotoxicity. The levels of these toxic HRE products positively correlate with cellular toxicity and phenotypic severity across multiple disease models. Moreover, the degree of epigenetic repression inversely correlates with some facets of clinical presentation in C9-ALS patients. Recently, bacterial artificial chromosomes (BAC) have been used to generate transgenic mice that harbor the HRE mutation, complementing other relevant model systems such as patient-derived induced pluripotent stem cells (iPSCs). While epigenetic features of the HRE have been investigated in various model systems and post-mortem tissues, epigenetic dysregulation at the expanded locus in C9-BAC mice remains unexplored. METHODS AND RESULTS Here, we sought to determine whether clinically relevant epigenetic perturbations caused by the HRE are mirrored in a C9-BAC mouse model. We used complementary DNA methylation assessment and immunoprecipitation methods to demonstrate that epigenetic aberrations caused by the HRE, such as DNA and histone methylation, are recapitulated in the C9-BAC mice. Strikingly, we found that cytosine hypermethylation within the promoter region of the human transgene occurred in a subset of C9-BAC mice similar to what is observed in patient populations. Moreover, we show that partial heterochromatinization of the C9 HRE occurs during the first weeks of the mouse lifespan, indicating age-dependent epigenetic repression. Using iPSC neurons, we found that preventing R-loop formation did not impede heterochromatinization of the HRE. CONCLUSIONS Taken together, these observations provide further insight into mechanism and developmental time-course of epigenetic perturbations conferred by the C9ORF72 HRE. Finally, we suggest that epigenetic repression of the C9ORF72 HRE and nearby gene promoter could impede or delay motor neuron degeneration in C9-BAC mouse models of ALS/FTD.
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17
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Dolinnaya NG, Ogloblina AM, Yakubovskaya MG. Structure, Properties, and Biological Relevance of the DNA and RNA G-Quadruplexes: Overview 50 Years after Their Discovery. BIOCHEMISTRY (MOSCOW) 2017; 81:1602-1649. [PMID: 28260487 PMCID: PMC7087716 DOI: 10.1134/s0006297916130034] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
G-quadruplexes (G4s), which are known to have important roles in regulation of key biological processes in both normal and pathological cells, are the most actively studied non-canonical structures of nucleic acids. In this review, we summarize the results of studies published in recent years that change significantly scientific views on various aspects of our understanding of quadruplexes. Modern notions on the polymorphism of DNA quadruplexes, on factors affecting thermodynamics and kinetics of G4 folding–unfolding, on structural organization of multiquadruplex systems, and on conformational features of RNA G4s and hybrid DNA–RNA G4s are discussed. Here we report the data on location of G4 sequence motifs in the genomes of eukaryotes, bacteria, and viruses, characterize G4-specific small-molecule ligands and proteins, as well as the mechanisms of their interactions with quadruplexes. New information on the structure and stability of G4s in telomeric DNA and oncogene promoters is discussed as well as proof being provided on the occurrence of G-quadruplexes in cells. Prominence is given to novel experimental techniques (single molecule manipulations, optical and magnetic tweezers, original chemical approaches, G4 detection in situ, in-cell NMR spectroscopy) that facilitate breakthroughs in the investigation of the structure and functions of G-quadruplexes.
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Affiliation(s)
- N G Dolinnaya
- Lomonosov Moscow State University, Department of Chemistry, Moscow, 119991, Russia.
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Kumar V, kashav T, Islam A, Ahmad F, Hassan MI. Structural insight into C9orf72 hexanucleotide repeat expansions: Towards new therapeutic targets in FTD-ALS. Neurochem Int 2016; 100:11-20. [DOI: 10.1016/j.neuint.2016.08.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 08/12/2016] [Accepted: 08/12/2016] [Indexed: 12/12/2022]
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Richard P, Manley JL. R Loops and Links to Human Disease. J Mol Biol 2016; 429:3168-3180. [PMID: 27600412 DOI: 10.1016/j.jmb.2016.08.031] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 08/26/2016] [Accepted: 08/31/2016] [Indexed: 12/13/2022]
Abstract
Aberrant R-loop structures are increasingly being realized as an important contributor to human disease. R loops, which are mainly co-transcriptional, abundant RNA/DNA hybrids, form naturally and can indeed be beneficial for transcription regulation at certain loci. However, their unwanted persistence elsewhere or in particular situations can lead to DNA double-strand breaks, chromosome rearrangements, and hypermutation, which are all sources of genomic instability. Mutations in genes involved in R-loop resolution or mutations leading to R-loop formation at specific genes affect the normal physiology of the cell. We discuss here the examples of diseases for which a link with R loops has been described, as well as how disease-causing mutations might participate in the development and/or progression of diseases that include repeat-associated conditions, other neurological disorders, and cancers.
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Affiliation(s)
- Patricia Richard
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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The expanding biology of the C9orf72 nucleotide repeat expansion in neurodegenerative disease. Nat Rev Neurosci 2016; 17:383-95. [PMID: 27150398 DOI: 10.1038/nrn.2016.38] [Citation(s) in RCA: 151] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A nucleotide repeat expansion (NRE) within the chromosome 9 open reading frame 72 (C9orf72) gene was the first of this type of mutation to be linked to multiple neurological conditions, including amyotrophic lateral sclerosis and frontotemporal dementia. The pathogenic mechanisms through which the C9orf72 NRE contributes to these disorders include loss of C9orf72 function and gain-of-function mechanisms of C9orf72 driven by toxic RNA and protein species encoded by the NRE. These mechanisms have been linked to several cellular defects - including nucleocytoplasmic trafficking deficits and nuclear stress - that have been observed in both patients and animal models.
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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]
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Distribution of dipeptide repeat proteins in cellular models and C9orf72 mutation cases suggests link to transcriptional silencing. Acta Neuropathol 2015; 130:537-55. [PMID: 26085200 PMCID: PMC4575390 DOI: 10.1007/s00401-015-1450-z] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 05/25/2015] [Accepted: 06/03/2015] [Indexed: 12/12/2022]
Abstract
A massive expansion of a GGGGCC repeat upstream of the C9orf72 coding region is the most common known cause of amyotrophic lateral sclerosis and frontotemporal dementia. Despite its intronic localization and lack of a canonical start codon, both strands are translated into aggregating dipeptide repeat (DPR) proteins: poly-GA, poly-GP, poly-GR, poly-PR and poly-PA. To address conflicting findings on the predominant toxicity of the different DPR species in model systems, we compared the expression pattern of the DPR proteins in rat primary neurons and postmortem brain and spinal cord of C9orf72 mutation patients. Only poly-GA overexpression closely mimicked the p62-positive neuronal cytoplasmic inclusions commonly observed for all DPR proteins in patients. In contrast, overexpressed poly-GR and poly-PR formed nucleolar p62-negative inclusions. In patients, most of the less common neuronal intranuclear DPR inclusions were para-nucleolar and p62 positive. Neuronal nucleoli in C9orf72 cases showed normal size and morphology regardless of the presence of poly-GR and poly-PR inclusions arguing against widespread nucleolar stress, reported in cellular models. Colocalization of para-nucleolar DPR inclusions with heterochromatin and a marker of transcriptional repression (H3K9me2) indicates a link to gene transcription. In contrast, we detected numerous intranuclear DPR inclusions not associated with nucleolar structures in ependymal and subependymal cells. In patients, neuronal inclusions of poly-GR, poly-GP and the poly-GA interacting protein Unc119 were less abundant than poly-GA inclusions, but showed similar regional and subcellular distribution. Regardless of neurodegeneration, all inclusions were most abundant in neocortex, hippocampus and thalamus, with few inclusions in brain stem and spinal cord. In the granular cell layer of the cerebellum, poly-GA and Unc119 inclusions were significantly more abundant in cases with FTLD than in cases with MND and FTLD/MND. Poly-PR inclusions were rare throughout the brain but significantly more abundant in the CA3/4 region of FTLD cases than in MND cases. Thus, although DPR distribution is not correlated with neurodegeneration spatially, it correlates with neuropathological subtypes.
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Abstract
RNAs adopt diverse folded structures that are essential for function and thus play critical roles in cellular biology. A striking example of this is the ribosome, a complex, three-dimensionally folded macromolecular machine that orchestrates protein synthesis. Advances in RNA biochemistry, structural and molecular biology, and bioinformatics have revealed other non-coding RNAs whose functions are dictated by their structure. It is not surprising that aberrantly folded RNA structures contribute to disease. In this Review, we provide a brief introduction into RNA structural biology and then describe how RNA structures function in cells and cause or contribute to neurological disease. Finally, we highlight successful applications of rational design principles to provide chemical probes and lead compounds targeting structured RNAs. Based on several examples of well-characterized RNA-driven neurological disorders, we demonstrate how designed small molecules can facilitate the study of RNA dysfunction, elucidating previously unknown roles for RNA in disease, and provide lead therapeutics.
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Affiliation(s)
- Viachaslau Bernat
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Matthew D Disney
- Department of Chemistry, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA.
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Simone R, Fratta P, Neidle S, Parkinson GN, Isaacs AM. G-quadruplexes: Emerging roles in neurodegenerative diseases and the non-coding transcriptome. FEBS Lett 2015; 589:1653-68. [PMID: 25979174 DOI: 10.1016/j.febslet.2015.05.003] [Citation(s) in RCA: 164] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 04/29/2015] [Accepted: 05/02/2015] [Indexed: 12/14/2022]
Abstract
G-rich sequences in DNA and RNA have a propensity to fold into stable secondary structures termed G-quadruplexes. G-quadruplex forming sequences are widespread throughout the human genome, within both, protein coding and non-coding genes, and regulatory regions. G-quadruplexes have been implicated in multiple cellular functions including chromatin epigenetic regulation, DNA recombination, transcriptional regulation of gene promoters and enhancers, and translation. Here we will review the evidence for the occurrence of G-quadruplexes both in vitro and in vivo; their role in neurological diseases including G-quadruplex-forming repeat expansions in the C9orf72 gene in frontotemporal dementia and amyotrophic lateral sclerosis and loss of the G-quadruplex binding protein FMRP in the intellectual disability fragile X syndrome. We also review mounting evidence that supports a role for G-quadruplexes in regulating the processing or function of a range of non-coding RNAs. Finally we will highlight current perspectives for therapeutic interventions that target G-quadruplexes.
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Affiliation(s)
- Roberto Simone
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.
| | - Pietro Fratta
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK; Sobell Department of Motor Neuroscience and Movement, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
| | - Stephen Neidle
- UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
| | - Gary N Parkinson
- UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.
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