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Verbeeren J, Teixeira J, Garcia SMDA. The Muscleblind-like protein MBL-1 regulates microRNA expression in Caenorhabditis elegans through an evolutionarily conserved autoregulatory mechanism. PLoS Genet 2023; 19:e1011109. [PMID: 38134228 PMCID: PMC10773944 DOI: 10.1371/journal.pgen.1011109] [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: 06/16/2023] [Revised: 01/08/2024] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
The Muscleblind-like (MBNL) family is a highly conserved set of RNA-binding proteins (RBPs) that regulate RNA metabolism during the differentiation of various animal tissues. Functional insufficiency of MBNL affects muscle and central nervous system development, and contributes to the myotonic dystrophies (DM), a set of incurable multisystemic disorders. Studies on the regulation of MBNL genes are essential to provide insight into the gene regulatory networks controlled by MBNL proteins and to understand how dysregulation within these networks causes disease. In this study, we demonstrate the evolutionary conservation of an autoregulatory mechanism that governs the function of MBNL proteins by generating two distinct protein isoform types through alternative splicing. Our aim was to further our understanding of the regulatory principles that underlie this conserved feedback loop in a whole-organismal context, and to address the biological significance of the respective isoforms. Using an alternative splicing reporter, our studies show that, during development of the Caenorhabditis elegans central nervous system, the orthologous mbl-1 gene shifts production from long protein isoforms that localize to the nucleus to short isoforms that also localize to the cytoplasm. Using isoform-specific CRISPR/Cas9-generated strains, we showed that expression of short MBL-1 protein isoforms is required for healthy neuromuscular function and neurodevelopment, while expression of long MBL-1 protein isoforms is dispensable, emphasizing a key role for cytoplasmic functionalities of the MBL-1 protein. Furthermore, RNA-seq and lifespan analyses indicated that short MBL-1 isoforms are crucial regulators of miRNA expression and, in consequence, required for normal lifespan. In conclusion, this study provides support for the disruption of cytoplasmic RNA metabolism as a contributor in myotonic dystrophy and paves the way for further exploration of miRNA regulation through MBNL proteins during development and in disease models.
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Affiliation(s)
- Jens Verbeeren
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Joana Teixeira
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
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Huang K, Wang DD, Hu WB, Zeng WQ, Xu X, Li QX, Bi FF, Yang H, Qiu J. Calcitriol increases MBNL1 expression and alleviates myotonic dystrophy phenotypes in HSA LR mouse models. J Transl Med 2022; 20:588. [PMID: 36510245 PMCID: PMC9743610 DOI: 10.1186/s12967-022-03806-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 12/02/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Myotonic dystrophy type 1 (DM1), one of the most common forms of adult-onset muscular dystrophy, is caused by abnormally expanded CTG repeats in the 3' untranslated region of the DMPK gene. The CUG repeats transcribed from the expanded CTG repeats sequestrate a splicing factor, MBNL1, causing the clinical symptoms in DM1. Nowadays, only symptomatic treatments are available for DM1, and no rational therapy is available. Recently, upregulation of MBNL1 expression has been found to be one of the promising therapies for DM1. METHODS All experiments were conducted in the C2C12 myoblasts and HSALR mice, a DM1 mouse model. Real-time PCR and western blot were used to detect the mRNA and protein level, respectively. The rotarod exercise, grip strength and hanging time were used to evaluate the muscle strength of mice. RESULTS In this study, we demonstrated that calcitriol, an active form of vitamin D3, increased MBNL1 in C2C12 mouse myoblasts as well as in HSALR mice model for DM1. In HSALR mice model, calcitriol improved muscle strength, and corrected aberrant splicing in skeletal muscle. Besides, calcitriol reduced the number of central nuclei, and improved muscle histopathology in HSALR mice. In addition, we identified that calcitriol upregulated MBNL1 expression via activating the promoter of Mbnl1 in C2C12 myogenic cells. CONCLUSION Our study suggests that calcitriol is a potential pharmacological strategy for DM1 that enhances MBNL1 expression.
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Affiliation(s)
- Kun Huang
- grid.216417.70000 0001 0379 7164Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan China ,grid.216417.70000 0001 0379 7164Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan China ,grid.216417.70000 0001 0379 7164National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan China
| | - Dan-Dan Wang
- grid.216417.70000 0001 0379 7164Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan China ,grid.216417.70000 0001 0379 7164National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan China
| | - Wen-Bao Hu
- grid.216417.70000 0001 0379 7164Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan China ,grid.216417.70000 0001 0379 7164National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan China
| | - Wei-Qian Zeng
- grid.216417.70000 0001 0379 7164Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan China ,grid.216417.70000 0001 0379 7164National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan China
| | - Xia Xu
- grid.216417.70000 0001 0379 7164Department of General Medicine, Xiangya Hospital, Central South University, Changsha, Hunan China ,grid.216417.70000 0001 0379 7164National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan China
| | - Qiu-Xiang Li
- grid.216417.70000 0001 0379 7164Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan China ,grid.216417.70000 0001 0379 7164National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan China
| | - Fang-Fang Bi
- grid.216417.70000 0001 0379 7164Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan China ,grid.216417.70000 0001 0379 7164National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan China
| | - Huan Yang
- grid.216417.70000 0001 0379 7164Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan China ,grid.216417.70000 0001 0379 7164National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan China
| | - Jian Qiu
- grid.216417.70000 0001 0379 7164Hunan Key Laboratory of Molecular Precision Medicine, Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan China ,grid.216417.70000 0001 0379 7164Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan China ,grid.216417.70000 0001 0379 7164National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan China
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Ozimski LL, Sabater-Arcis M, Bargiela A, Artero R. The hallmarks of myotonic dystrophy type 1 muscle dysfunction. Biol Rev Camb Philos Soc 2020; 96:716-730. [PMID: 33269537 DOI: 10.1111/brv.12674] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 11/18/2020] [Accepted: 11/20/2020] [Indexed: 12/20/2022]
Abstract
Myotonic dystrophy type 1 (DM1) is the most prevalent form of muscular dystrophy in adults and yet there are currently no treatment options. Although this disease causes multisystemic symptoms, it is mainly characterised by myopathy or diseased muscles, which includes muscle weakness, atrophy, and myotonia, severely affecting the lives of patients worldwide. On a molecular level, DM1 is caused by an expansion of CTG repeats in the 3' untranslated region (3'UTR) of the DM1 Protein Kinase (DMPK) gene which become pathogenic when transcribed into RNA forming ribonuclear foci comprised of auto complementary CUG hairpin structures that can bind proteins. This leads to the sequestration of the muscleblind-like (MBNL) family of proteins, depleting them, and the abnormal stabilisation of CUGBP Elav-like family member 1 (CELF1), enhancing it. Traditionally, DM1 research has focused on this RNA toxicity and how it alters MBNL and CELF1 functions as key splicing regulators. However, other proteins are affected by the toxic DMPK RNA and there is strong evidence that supports various signalling cascades playing an important role in DM1 pathogenesis. Specifically, the impairment of protein kinase B (AKT) signalling in DM1 increases autophagy, apoptosis, and ubiquitin-proteasome activity, which may also be affected in DM1 by AMP-activated protein kinase (AMPK) downregulation. AKT also regulates CELF1 directly, by affecting its subcellular localisation, and indirectly as it inhibits glycogen synthase kinase 3 beta (GSK3β), which stabilises the repressive form of CELF1 in DM1. Another kinase that contributes to CELF1 mis-regulation, in this case by hyperphosphorylation, is protein kinase C (PKC). Additionally, it has been demonstrated that fibroblast growth factor-inducible 14 (Fn14) is induced in DM1 and is associated with downstream signalling through the nuclear factor κB (NFκB) pathways, associating inflammation with this disease. Furthermore, MBNL1 and CELF1 play a role in cytoplasmic processes involved in DM1 myopathy, altering proteostasis and sarcomere structure. Finally, there are many other elements that could contribute to the muscular phenotype in DM1 such as alterations to satellite cells, non-coding RNA metabolism, calcium dysregulation, and repeat-associated non-ATG (RAN) translation. This review aims to organise the currently dispersed knowledge on the different pathways affected in DM1 and discusses the unexplored connections that could potentially help in providing new therapeutic targets in DM1 research.
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Affiliation(s)
- Lauren L Ozimski
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menéndez Pelayo 4 acc., Valencia, 46010, Spain.,University Institute for Biotechnology and Biomedicine, Dr. Moliner 50, Burjasot, Valencia, 46100, Spain.,CIPF-INCLIVA Joint Unit, Valencia, 46012, Spain.,Arthex Biotech, Catedrático Escardino, 9, Paterna, Valencia, 46980, Spain
| | - Maria Sabater-Arcis
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menéndez Pelayo 4 acc., Valencia, 46010, Spain.,University Institute for Biotechnology and Biomedicine, Dr. Moliner 50, Burjasot, Valencia, 46100, Spain.,CIPF-INCLIVA Joint Unit, Valencia, 46012, Spain
| | - Ariadna Bargiela
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menéndez Pelayo 4 acc., Valencia, 46010, Spain.,University Institute for Biotechnology and Biomedicine, Dr. Moliner 50, Burjasot, Valencia, 46100, Spain.,CIPF-INCLIVA Joint Unit, Valencia, 46012, Spain
| | - Ruben Artero
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menéndez Pelayo 4 acc., Valencia, 46010, Spain.,University Institute for Biotechnology and Biomedicine, Dr. Moliner 50, Burjasot, Valencia, 46100, Spain.,CIPF-INCLIVA Joint Unit, Valencia, 46012, Spain
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An Overview of Alternative Splicing Defects Implicated in Myotonic Dystrophy Type I. Genes (Basel) 2020; 11:genes11091109. [PMID: 32971903 PMCID: PMC7564762 DOI: 10.3390/genes11091109] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/14/2020] [Accepted: 09/17/2020] [Indexed: 01/02/2023] Open
Abstract
Myotonic dystrophy type I (DM1) is the most common form of adult muscular dystrophy, caused by expansion of a CTG triplet repeat in the 3′ untranslated region (3′UTR) of the myotonic dystrophy protein kinase (DMPK) gene. The pathological CTG repeats result in protein trapping by expanded transcripts, a decreased DMPK translation and the disruption of the chromatin structure, affecting neighboring genes expression. The muscleblind-like (MBNL) and CUG-BP and ETR-3-like factors (CELF) are two families of tissue-specific regulators of developmentally programmed alternative splicing that act as antagonist regulators of several pre-mRNA targets, including troponin 2 (TNNT2), insulin receptor (INSR), chloride channel 1 (CLCN1) and MBNL2. Sequestration of MBNL proteins and up-regulation of CELF1 are key to DM1 pathology, inducing a spliceopathy that leads to a developmental remodelling of the transcriptome due to an adult-to-foetal splicing switch, which results in the loss of cell function and viability. Moreover, recent studies indicate that additional pathogenic mechanisms may also contribute to disease pathology, including a misregulation of cellular mRNA translation, localization and stability. This review focuses on the cause and effects of MBNL and CELF1 deregulation in DM1, describing the molecular mechanisms underlying alternative splicing misregulation for a deeper understanding of DM1 complexity. To contribute to this analysis, we have prepared a comprehensive list of transcript alterations involved in DM1 pathogenesis, as well as other deregulated mRNA processing pathways implications.
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Huang K, Masuda A, Chen G, Bushra S, Kamon M, Araki T, Kinoshita M, Ohkawara B, Ito M, Ohno K. Inhibition of cyclooxygenase-1 by nonsteroidal anti-inflammatory drugs demethylates MeR2 enhancer and promotes Mbnl1 transcription in myogenic cells. Sci Rep 2020; 10:2558. [PMID: 32054946 PMCID: PMC7018979 DOI: 10.1038/s41598-020-59517-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 01/30/2020] [Indexed: 12/12/2022] Open
Abstract
Muscleblind-like 1 (MBNL1) is a ubiquitously expressed RNA-binding protein, which is highly expressed in skeletal muscle. Abnormally expanded CUG-repeats in the DMPK gene cause myotonic dystrophy type 1 (DM1) by sequestration of MBNL1 to nuclear RNA foci and by upregulation of another RNA-binding protein, CUG-binding protein 1 (CUGBP1). We previously reported that a nonsteroidal anti-inflammatory drug (NSAID), phenylbutazone, upregulates MBNL1 expression in DM1 mouse model by demethylation of MeR2, an enhancer element in Mbnl1 intron 1. NSAIDs inhibit cyclooxygenase (COX), which is comprised of COX-1 and COX-2 isoforms. In this study, we screened 29 NSAIDs in C2C12 myoblasts, and found that 13 NSAIDs enhanced Mbnl1 expression, where COX-1-selective NSAIDs upregulated Mbnl1 more than COX-2-selective NSAIDs. Consistently, knockdown of COX-1, but not of COX-2, upregulated MBNL1 expression in C2C12 myoblasts and myotubes, as well as in myotubes differentiated from DM1 patient-derived induced pluripotent stem cells (iPSCs). Luciferase assay showed that COX-1-knockdown augmented the MeR2 enhancer activity. Furthermore, bisulfite sequencing analysis demonstrated that COX-1-knockdown suppressed methylation of MeR2. These results suggest that COX-1 inhibition upregulates Mbnl1 transcription through demethylation of the MeR2 enhancer. Taken together, our study provides new insights into the transcriptional regulation of Mbnl1 by the COX-1-mediated pathway.
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Affiliation(s)
- Kun Huang
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Akio Masuda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
| | - Guiying Chen
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Samira Bushra
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Masayoshi Kamon
- Department of Peripheral Nervous System Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Toshiyuki Araki
- Department of Peripheral Nervous System Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | | | - Bisei Ohkawara
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Mikako Ito
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Kinji Ohno
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
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Increased Muscleblind levels by chloroquine treatment improve myotonic dystrophy type 1 phenotypes in in vitro and in vivo models. Proc Natl Acad Sci U S A 2019; 116:25203-25213. [PMID: 31754023 DOI: 10.1073/pnas.1820297116] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is a life-threatening and chronically debilitating neuromuscular disease caused by the expansion of a CTG trinucleotide repeat in the 3' UTR of the DMPK gene. The mutant RNA forms insoluble structures capable of sequestering RNA binding proteins of the Muscleblind-like (MBNL) family, which ultimately leads to phenotypes. In this work, we demonstrate that treatment with the antiautophagic drug chloroquine was sufficient to up-regulate MBNL1 and 2 proteins in Drosophila and mouse (HSALR) models and patient-derived myoblasts. Extra Muscleblind was functional at the molecular level and improved splicing events regulated by MBNLs in all disease models. In vivo, chloroquine restored locomotion, rescued average cross-sectional muscle area, and extended median survival in DM1 flies. In HSALR mice, the drug restored muscular strength and histopathology signs and reduced the grade of myotonia. Taken together, these results offer a means to replenish critically low MBNL levels in DM1.
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Li JSS, Millard SS. Deterministic splicing of Dscam2 is regulated by Muscleblind. SCIENCE ADVANCES 2019; 5:eaav1678. [PMID: 30746474 PMCID: PMC6357765 DOI: 10.1126/sciadv.aav1678] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/04/2018] [Indexed: 06/09/2023]
Abstract
Alternative splicing increases the proteome diversity crucial for establishing the complex circuitry between trillions of neurons. To provide individual cells with different repertoires of protein isoforms, however, this process must be regulated. Previously, we found that the mutually exclusive alternative splicing of Drosophila Dscam2 produces two isoforms (A and B) with unique binding properties. This splicing event is cell type specific, and the transmembrane proteins that it generates are crucial for the development of axons, dendrites, and synapses. Here, we show that Muscleblind (Mbl) controls Dscam2 alternative splicing. Mbl represses isoform A and promotes the selection of isoform B. Mbl mutants exhibit phenotypes also observed in flies engineered to express a single Dscam2 isoform. Consistent with this, mbl expression is cell type specific and correlates with the splicing of isoform B. Our study demonstrates how the regulated expression of a splicing factor is sufficient to provide neurons with unique protein isoforms crucial for development.
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Fishilevich S, Nudel R, Rappaport N, Hadar R, Plaschkes I, Iny Stein T, Rosen N, Kohn A, Twik M, Safran M, Lancet D, Cohen D. GeneHancer: genome-wide integration of enhancers and target genes in GeneCards. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2017; 2017:3737828. [PMID: 28605766 PMCID: PMC5467550 DOI: 10.1093/database/bax028] [Citation(s) in RCA: 652] [Impact Index Per Article: 93.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 03/10/2017] [Indexed: 12/14/2022]
Abstract
A major challenge in understanding gene regulation is the unequivocal identification of enhancer elements and uncovering their connections to genes. We present GeneHancer, a novel database of human enhancers and their inferred target genes, in the framework of GeneCards. First, we integrated a total of 434 000 reported enhancers from four different genome-wide databases: the Encyclopedia of DNA Elements (ENCODE), the Ensembl regulatory build, the functional annotation of the mammalian genome (FANTOM) project and the VISTA Enhancer Browser. Employing an integration algorithm that aims to remove redundancy, GeneHancer portrays 285 000 integrated candidate enhancers (covering 12.4% of the genome), 94 000 of which are derived from more than one source, and each assigned an annotation-derived confidence score. GeneHancer subsequently links enhancers to genes, using: tissue co-expression correlation between genes and enhancer RNAs, as well as enhancer-targeted transcription factor genes; expression quantitative trait loci for variants within enhancers; and capture Hi-C, a promoter-specific genome conformation assay. The individual scores based on each of these four methods, along with gene–enhancer genomic distances, form the basis for GeneHancer’s combinatorial likelihood-based scores for enhancer–gene pairing. Finally, we define ‘elite’ enhancer–gene relations reflecting both a high-likelihood enhancer definition and a strong enhancer–gene association. GeneHancer predictions are fully integrated in the widely used GeneCards Suite, whereby candidate enhancers and their annotations are displayed on every relevant GeneCard. This assists in the mapping of non-coding variants to enhancers, and via the linked genes, forms a basis for variant–phenotype interpretation of whole-genome sequences in health and disease. Database URL:http://www.genecards.org/
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Affiliation(s)
- Simon Fishilevich
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ron Nudel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Noa Rappaport
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Rotem Hadar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Inbar Plaschkes
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Tsippi Iny Stein
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Naomi Rosen
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Asher Kohn
- LifeMap Sciences Inc, Marshfield, MA 02050, USA
| | - Michal Twik
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Marilyn Safran
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Doron Lancet
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Dana Cohen
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
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Konieczny P, Stepniak-Konieczna E, Taylor K, Sznajder LJ, Sobczak K. Autoregulation of MBNL1 function by exon 1 exclusion from MBNL1 transcript. Nucleic Acids Res 2017; 45:1760-1775. [PMID: 27903900 PMCID: PMC5389549 DOI: 10.1093/nar/gkw1158] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 11/07/2016] [Indexed: 01/14/2023] Open
Abstract
Muscleblind-like proteins (MBNLs) are regulators of RNA metabolism. During tissue differentiation the level of MBNLs increases, while their functional insufficiency plays a crucial role in myotonic dystrophy (DM). Deep sequencing of RNA molecules cross-linked to immunoprecipitated protein particles (CLIP-seq) revealed that MBNL1 binds to MBNL1 exon 1 (e1) encoding both the major part of 5΄UTR and an amino-terminal region of MBNL1 protein. We tested several hypotheses regarding the possible autoregulatory function of MBNL1 binding to its own transcript. Our data indicate that MBNLs induce skipping of e1 from precursor MBNL1 mRNA and that e1 exclusion may impact transcript association with polysomes and translation. Furthermore, e1-deficient protein isoform lacking the first two zinc fingers is highly unstable and its EGFP fusion protein has severely compromised splicing activity. We also show that MBNL1 can be transcribed from three different promoters and that the transcription initiation site determines the mode of e1 regulation. Taken together, we demonstrate that MBNL proteins control steady-state levels of MBNL1 through an interaction with e1 in its precursor mRNA. Insights from our study open a new avenue in therapies against DM based on manipulation of the transcription initiation site and e1 splicing of MBNL1 mRNA.
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Affiliation(s)
- Patryk Konieczny
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Ewa Stepniak-Konieczna
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Katarzyna Taylor
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Lukasz J Sznajder
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Krzysztof Sobczak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
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Fishilevich S, Nudel R, Rappaport N, Hadar R, Plaschkes I, Iny Stein T, Rosen N, Kohn A, Twik M, Safran M, Lancet D, Cohen D. GeneHancer: genome-wide integration of enhancers and target genes in GeneCards. Database (Oxford) 2017; 2017:3737828. [PMID: 28605766 DOI: 10.1093/database/bax028/3737828] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 03/10/2017] [Indexed: 05/26/2023]
Abstract
UNLABELLED A major challenge in understanding gene regulation is the unequivocal identification of enhancer elements and uncovering their connections to genes. We present GeneHancer, a novel database of human enhancers and their inferred target genes, in the framework of GeneCards. First, we integrated a total of 434 000 reported enhancers from four different genome-wide databases: the Encyclopedia of DNA Elements (ENCODE), the Ensembl regulatory build, the functional annotation of the mammalian genome (FANTOM) project and the VISTA Enhancer Browser. Employing an integration algorithm that aims to remove redundancy, GeneHancer portrays 285 000 integrated candidate enhancers (covering 12.4% of the genome), 94 000 of which are derived from more than one source, and each assigned an annotation-derived confidence score. GeneHancer subsequently links enhancers to genes, using: tissue co-expression correlation between genes and enhancer RNAs, as well as enhancer-targeted transcription factor genes; expression quantitative trait loci for variants within enhancers; and capture Hi-C, a promoter-specific genome conformation assay. The individual scores based on each of these four methods, along with gene–enhancer genomic distances, form the basis for GeneHancer’s combinatorial likelihood-based scores for enhancer–gene pairing. Finally, we define ‘elite’ enhancer–gene relations reflecting both a high-likelihood enhancer definition and a strong enhancer–gene association. GeneHancer predictions are fully integrated in the widely used GeneCards Suite, whereby candidate enhancers and their annotations are displayed on every relevant GeneCard. This assists in the mapping of non-coding variants to enhancers, and via the linked genes, forms a basis for variant–phenotype interpretation of whole-genome sequences in health and disease. DATABASE URL http://www.genecards.org/.
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Affiliation(s)
- Simon Fishilevich
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ron Nudel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Noa Rappaport
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Rotem Hadar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Inbar Plaschkes
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Tsippi Iny Stein
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Naomi Rosen
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Asher Kohn
- LifeMap Sciences Inc, Marshfield, MA 02050, USA
| | - Michal Twik
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Marilyn Safran
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Doron Lancet
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Dana Cohen
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
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11
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Chen G, Masuda A, Konishi H, Ohkawara B, Ito M, Kinoshita M, Kiyama H, Matsuura T, Ohno K. Phenylbutazone induces expression of MBNL1 and suppresses formation of MBNL1-CUG RNA foci in a mouse model of myotonic dystrophy. Sci Rep 2016; 6:25317. [PMID: 27126921 PMCID: PMC4850456 DOI: 10.1038/srep25317] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 04/15/2016] [Indexed: 12/11/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is caused by abnormal expansion of CTG repeats in the 3′ untranslated region of the DMPK gene. Expanded CTG repeats are transcribed into RNA and make an aggregate with a splicing regulator, MBNL1, in the nucleus, which is called the nuclear foci. The nuclear foci sequestrates and downregulates availability of MBNL1. Symptomatic treatments are available for DM1, but no rational therapy is available. In this study, we found that a nonsteroidal anti-inflammatory drug (NSAID), phenylbutazone (PBZ), upregulated the expression of MBNL1 in C2C12 myoblasts as well as in the HSALR mouse model for DM1. In the DM1 mice model, PBZ ameliorated aberrant splicing of Clcn1, Nfix, and Rpn2. PBZ increased expression of skeletal muscle chloride channel, decreased abnormal central nuclei of muscle fibers, and improved wheel-running activity in HSALR mice. We found that the effect of PBZ was conferred by two distinct mechanisms. First, PBZ suppressed methylation of an enhancer region in Mbnl1 intron 1, and enhanced transcription of Mbnl1 mRNA. Second, PBZ attenuated binding of MBNL1 to abnormally expanded CUG repeats in cellulo and in vitro. Our studies suggest that PBZ is a potent therapeutic agent for DM1 that upregulates availability of MBNL1.
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Affiliation(s)
- Guiying Chen
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Akio Masuda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroyuki Konishi
- Division of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Bisei Ohkawara
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Mikako Ito
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masanobu Kinoshita
- Department of Frontier Health Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo, Japan
| | - Hiroshi Kiyama
- Division of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tohru Matsuura
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan.,Division of Neurology, Department of Medicine, Jichi Medical University, Shimotsuke, Japan
| | - Kinji Ohno
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya, Japan
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12
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Bargiela A, Cerro-Herreros E, Fernandez-Costa JM, Vilchez JJ, Llamusi B, Artero R. Increased autophagy and apoptosis contribute to muscle atrophy in a myotonic dystrophy type 1 Drosophila model. Dis Model Mech 2016; 8:679-90. [PMID: 26092529 PMCID: PMC4486854 DOI: 10.1242/dmm.018127] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Muscle mass wasting is one of the most debilitating symptoms of myotonic dystrophy type 1 (DM1) disease, ultimately leading to immobility, respiratory defects, dysarthria, dysphagia and death in advanced stages of the disease. In order to study the molecular mechanisms leading to the degenerative loss of adult muscle tissue in DM1, we generated an inducible Drosophila model of expanded CTG trinucleotide repeat toxicity that resembles an adult-onset form of the disease. Heat-shock induced expression of 480 CUG repeats in adult flies resulted in a reduction in the area of the indirect flight muscles. In these model flies, reduction of muscle area was concomitant with increased apoptosis and autophagy. Inhibition of apoptosis or autophagy mediated by the overexpression of DIAP1, mTOR (also known as Tor) or muscleblind, or by RNA interference (RNAi)-mediated silencing of autophagy regulatory genes, achieved a rescue of the muscle-loss phenotype. In fact, mTOR overexpression rescued muscle size to a size comparable to that in control flies. These results were validated in skeletal muscle biopsies from DM1 patients in which we found downregulated autophagy and apoptosis repressor genes, and also in DM1 myoblasts where we found increased autophagy. These findings provide new insights into the signaling pathways involved in DM1 disease pathogenesis.
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Affiliation(s)
- Ariadna Bargiela
- Translational Genomics Group, Department of Genetics, University of Valencia, Burjassot 46100, Spain INCLIVA Health Research Institute, Valencia 46010, Spain
| | - Estefanía Cerro-Herreros
- Translational Genomics Group, Department of Genetics, University of Valencia, Burjassot 46100, Spain INCLIVA Health Research Institute, Valencia 46010, Spain
| | - Juan M Fernandez-Costa
- Translational Genomics Group, Department of Genetics, University of Valencia, Burjassot 46100, Spain
| | - Juan J Vilchez
- Neurology Section, Hospital Universitari La Fe, Valencia 46026, Spain Department of Internal Medicine, University of Valencia, Valencia 46010, Spain Centro de Investigaciones Biomedicas en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Institute Carlos III, Ministry of Economy and Competitiveness, Madrid 28049, Spain
| | | | - Ruben Artero
- Translational Genomics Group, Department of Genetics, University of Valencia, Burjassot 46100, Spain INCLIVA Health Research Institute, Valencia 46010, Spain
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Konieczny P, Stepniak-Konieczna E, Sobczak K. MBNL proteins and their target RNAs, interaction and splicing regulation. Nucleic Acids Res 2014; 42:10873-87. [PMID: 25183524 PMCID: PMC4176163 DOI: 10.1093/nar/gku767] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Muscleblind-like (MBNL) proteins are key regulators of precursor and mature mRNA metabolism in mammals. Based on published and novel data, we explore models of tissue-specific MBNL interaction with RNA. We portray MBNL domains critical for RNA binding and splicing regulation, and the structure of MBNL's normal and pathogenic RNA targets, particularly in the context of myotonic dystrophy (DM), in which expanded CUG or CCUG repeat transcripts sequester several nuclear proteins including MBNLs. We also review the properties of MBNL/RNA complex, including recent data obtained from UV cross-linking and immunoprecipitation (CLIP-Seq), and discuss how this interaction shapes normal MBNL-dependent alternative splicing regulation. Finally, we review how this acquired knowledge about the pathogenic RNA structure and nature of MBNL sequestration can be translated into the design of therapeutic strategies against DM.
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Affiliation(s)
- Patryk Konieczny
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Ewa Stepniak-Konieczna
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Krzysztof Sobczak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
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