Antagonistic role of MBNL1 and LIN28 promotes specific alteration of pre-miR-1 processing and is associated with heart defects in DM
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE24109 | GEO | 2011/05/26
SECONDARY ACCESSION(S): PRJNA130201
REPOSITORIES: GEO
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Project description:Myotonic dystrophy type 1 (DM1), the most common muscular dystrophy in adults, is caused by the expression of expanded CUG repeats, which sequester the MBNL1 RNA binding protein. Cardiac involvement, which is characterized by conduction defects and arrhythmias, is the second cause of death of DM1 patients. Down-expression of miR-1 in mice leads to cardiac conduction disturbances and to arrhythmias. Here, we show that miR-1 expression is decreased in DM1 hearts, due to a mis-regulation of the processing of pre-miR-1. MBNL1 binds to UGC motifs located within the pre-miR-1 loop and competes binding of LIN28, which promotes uridylation and blocks pre-miR-1 processing. Finally and consistent with a down-regulation of miR-1, known, GJA1, and novel, CACNA1C, targets of miR-1 are increased in DM1 hearts. CACNA1C and GJA1 encode the main calcium and gap junction channels in heart, respectively, and their mis-regulation may contribute to the heart arrythmias and conduction defects observed in DM1 patients. Total RNA of 3 control and 3 CDM1 primary culture of muscle cells differentiated 10 days into myotubes was extracted using Trizol and analyzed by Agilent microarray.
2011-05-26 | E-GEOD-24109 | biostudies-arrayexpress
Project description:Mapping MBNL-regulated genome-wide alternative polyadenylation: We report that depletion of Mbnl proteins in mouse embryo fibroblasts (MEFs), DM mouse model quadriceps muscle, and DM-autopsy muscle tissue leads to mis-regulation of alternative polyadenylation We compared WT, Mbnl1/2KO, Mbnl1/2KO/3siRNA, and Mbnl1/2KO/scrambled siRNA MEFs (n=2 for each group) to evaluate alternative polyadenylation shifts that occur due to progressive loss of Mbnl proteins. We also compared WT (1 day old, and 4 months old, n=2 each) and HSALR mouse model (4 months old, n=2) of myotonic dystrophy for developmental alternative polyadenylation defects in myotonic dystrophy. Finally, we compared control and DM1 autopsy muscle tissues (n=3) for changes in alternative polyadenylation. We performed HITS-CLIP analysis of binding sites of Mbnl1, Mbnl2 and Mbnl3 in MEFs (n=3 each). We also performed HITS-CLIP analysis for major skeletal muscle Mbnl protein, Mbnl1 in FVB WT adult muscle (4 months, n=3). Finally we performed HITS-CLIP analysis for CPSF6 in WT and Mbnl1/2 KO MEFs (n=3 each) Please note that the 'readme_Table.txt' describes the contents of 'Table S*.xlsx' files, and the readme_method.txt include additional details about experiemenal procedures.
2014-09-05 | E-GEOD-60487 | biostudies-arrayexpress
Project description:Distinct RNA-mediated impacts on alternative splicing and extracellular matrix gene expression in a mouse model of myotonic dystrophy. Myotonic dystrophy (DM1) is associated with expression of expanded CTG DNA repeats as RNA (CUGexp RNA). To test whether CUGexp RNA creates a global splicing defect, we compared skeletal muscle of two mouse DM1 models, one expressing a CTGexp transgene, and another homozygous for a defective Mbnl1 gene. Strong correlation in splicing changes for ~100 new Mbnl1-regulated exons indicates loss of Mbnl1 explains >80% of the splicing pathology due to CUGexp RNA. In contrast, only about half of mRNA level changes can be attributed to loss of Mbnl1, indicating CUGexp RNA has Mbnl1-independent effects, particularly on mRNAs for extracellular matrix (ECM) proteins. We propose that CUGexp RNA causes two separate effects: loss of Mbnl1 function, disrupting splicing, and loss of another function that disrupts ECM mRNA regulation, possibly mediated by MBNL2. These findings reveal unanticipated similarities between DM1 and other muscular dystrophies. MBNL1 knockout and HSALR mice on FVB background. To test whether CUGexp RNA creates a global splicing defect, we compared skeletal muscle of two mouse DM1 models, one expressing a CTGexp transgene, and another homozygous for a defective Mbnl1 gene. These samples were compared to the skeletal muscle of a wildtype mouse.
2010-01-23 | E-GEOD-17986 | biostudies-arrayexpress
Project description:This study tested candidate therapeutic antimiRs in a comprehensive new collection of primary myoblasts derived from myotonic dystrophy type 1 (DM1) patients. DM1 is caused by genetically unstable CTG repeat expansions in the DMPK gene and has multiple clinical presentations, likely because of variable repeat sizes at the tissue and organ levels. Expanded DMPK transcripts deplete Muscleblind-Like Splicing Regulator protein MBNL1, which in turn causes DM1 symptoms. A promising therapeutic approach increases the expression of MBNL1 by blocking natural repressors miR-23b and miR-218 employing antimiRs with chemical modifications designed for a better pharmacological profile in humans. In untreated primary cells, we demonstrate that upregulated therapeutic targets miR-23b and miR-218 and reduced MBNL1 protein levels inversely correlate with CTG repeat size, supporting that active MBNL1 protein repression synergizes with the sequestration by CUG repeats in DM1. Upon treatment with novel antimiRs, multiple readouts of RNA toxicity associated with typical DM1 alterations improved. MBNL1-dependent exon inclusions, and myoblast fusion and myotube area defects, showed robust correction over a wide range of CTG expansions. Unexpectedly, antimiR treatment also reduced DMPK transcript levels and the number of ribonuclear aggregates. Based on these data, we selected a leading antimiR for further transcriptomics characterization and demonstrated that it reversed up to 68% of dysregulated genes. The study revealed that the candidate antimiRs could provide therapy to clinically relevant DM1 forms over a wide range of repeat sizes and genetic backgrounds by simultaneously reducing MBNL1 sequestration and derepressing protein synthesis.
2024-05-01 | GSE237411 | GEO
Project description:Distinct RNA-mediated impacts on alternative splicing and extracellular matrix gene expression in a mouse model of myotonic dystrophy. Myotonic dystrophy (DM1) is associated with expression of expanded CTG DNA repeats as RNA (CUGexp RNA). To test whether CUGexp RNA creates a global splicing defect, we compared skeletal muscle of two mouse DM1 models, one expressing a CTGexp transgene, and another homozygous for a defective Mbnl1 gene. Strong correlation in splicing changes for ~100 new Mbnl1-regulated exons indicates loss of Mbnl1 explains >80% of the splicing pathology due to CUGexp RNA. In contrast, only about half of mRNA level changes can be attributed to loss of Mbnl1, indicating CUGexp RNA has Mbnl1-independent effects, particularly on mRNAs for extracellular matrix (ECM) proteins. We propose that CUGexp RNA causes two separate effects: loss of Mbnl1 function, disrupting splicing, and loss of another function that disrupts ECM mRNA regulation, possibly mediated by MBNL2. These findings reveal unanticipated similarities between DM1 and other muscular dystrophies.
2010-01-24 | GSE17986 | GEO
Project description:The symptoms of Myotonic Dystrophy Type 1 (DM1) are multi-systemic and life-threatening. The neuromuscular disorder is rooted in a non-coding CTG microsatellite expansion in the DMPK gene that is correctly transcribed and physically sequesters the MBNL family of proteins. The high-affinity binding occurring between the proteins and the repetitions disallows MBNL proteins from performing their post-transcriptional splicing regulation leading to downstream molecular effects directly related to disease symptoms such as myotonia and muscle weakness. In this study, we build off of previously demonstrated evidence showing that the silencing of miR-23b and miR-218 can increase MBNL1 and 2 protein in DM1 cells. Here we use blockmiR antisense technology to block the binding sites of these miRNAs in order to increase MBNL translation into protein without binding to the microRNAs in DM1 muscle cells. The blockmiRs show therapeutic effects with the rescue of mis-splicing, MBNL subcellular localization, and transcriptomic expression proving that this novel and highly specific strategy could be a potentially viable therapy in Vivo.
2022-07-31 | GSE173359 | GEO
Project description:Myotonic dystrophy type 1 (DM1) is a CTG microsatellite expansion (CTGexp) disorder caused by expression of CUGexp RNAs. These mutant RNAs alter the activities of RNA processing factors, including MBNL proteins, leading to reversion to specific fetal isoforms in adult tissues and DM1 pathology. While this pathogenesis model accounts for adult-onset disease, the molecular basis of congenital DM (CDM) is unknown. Here, we test the hypothesis that disruption of developmentally regulated RNA alternative processing pathways contributes to CDM disease. Analysis of alternative splicing (AS) transitions during human myogenesis reveals hundreds of AS events that undergo prenatal isoform transitions and both AS and alternative polyadenylation abnormalities are prominently detectable in infant CDM muscle biopsies. While the majority of RNA targets are also mis-regulated in adult-onset DM1, splicing dysregulation is significantly more severe in CDM. Since many of these mis-processing events are MBNL-regulated, we generated mouse Mbnl double (Mbnl1; Mbnl2) and triple (Mbnl1; Mbnl2; Mbnl3) muscle-specific knockout models that recapitulate the congenital myopathy, gene expression and spliceopathy defects characteristic of CDM. This study demonstrates RNA mis-processing is a major pathogenic factor in CDM and provides novel mouse models to further examine roles for co/post-transcriptional gene regulation during tissue development.
2017-07-12 | GSE97806 | GEO
Project description:Myotonic dystrophy type 1 (DM1) is a neuro-muscular disorder caused by CTG triplet expansion in the 3-UTR of the DMPK gene. Mutated transcripts aggregate in muscle nuclei and sequester the MBNL1 splicing factor. To assess the involvement of Mbl sequestration on transcriptpion deregulation in DM1, we performed genome wide analyses of gene expression of DM1 Drosophila model in three different genetic contexts: Mef>mblRNAi, Mef>600CTG, Mef>960CTG vs. Mef>lacZ control line.
2013-04-01 | E-MTAB-1469 | biostudies-arrayexpress
Project description:Myotonic dystrophy (dystrophia myotonica, DM) is caused by expansions of CTG (type 1; DM1) or CCTG (type 2; DM2) repeats in the non-coding regions of the DMPK and CNBP genes, and patients with DM1 or DM2 often suffer from sudden cardiac death due to lethal arrhythmia. Specific molecular changes that underlie DM cardiac pathology have been linked to repeat-associated depletion of Muscleblind-like (MBNL) 1 and 2 proteins and upregulation of CUGBP Elav-like family member 1. Aims: We aim to create an Mbnl KO mouse model recapitulating DM cardiogenic death not under anesthesia, since none of the DM mouse models have reached this goal. Besides, it is unclear whether dysfunction of cardiomyocytes, among other cell types in the heart, can solely drive phenotypes. Methods and Results: We generated Myh6-Cre DKO (Mbnl1-/-; Mbnl2cond/cond; Myh6-Cre+/-) mice that completely eliminate Mbnl1/2 expression in cardiomyocytes. In this model, we found increased myocardial fibrosis, dilated cardiomyopathy and various arrhythmias. Importantly, we observed spontaneous lethal arrhythmic events in the context of shortened lifespan. RNA sequencing (RNA-seq) revealed mis-splicing events involving sarcomeric structure, mitochondrial dynamics and vesicular trafficking that mimics DM hearts. Gene expression changes were also noted by RNA-seq, and confirmed by qPCR. Notably, immunoblotting revealed a nearly 6-fold increase of Calsequestrin 1 and 50% reduction of epidermal growth factor proteins. Conclusion: These results showed that complete elimination of MBNL1/2 in mouse cardiomyocytes is sufficient to elicit a full spectrum of DM cardiac phenotypes including cardiac-related sudden death, and therefore these mice could serve as a useful model for studying DM heart pathogenesis and related translational research.
2022-01-01 | GSE184574 | GEO
Project description:For some neurological disorders, disease is primarily RNA-mediated due to expression of non-coding microsatellite expansion RNAs (RNAexp). Toxicity is thought to result from enhanced binding of proteins to these expansions and depletion from their normal cellular targets. However, experimental evidence for this sequestration model is lacking. Here, we use HITS-CLIP and pre-mRNA processing analysis of human control versus myotonic dystrophy (DM) brains to provide compelling evidence for this RNA toxicity model. MBNL2 binds directly to DM repeat expansions in the brain resulting in depletion from its normal RNA targets with downstream effects on alternative splicing and polyadenylation. Similar RNA processing defects were detected in Mbnl compound knockout mice, highlighted by dysregulation of Mapt splicing and fetal tau isoform expression in adults. These results demonstrate that MBNL proteins are directly sequestered by RNAexp in the DM brain and introduce a powerful experimental tool to evaluate RNA-mediated toxicity in other expansion diseases. HITS-CLIP analysis was performed to identify RNA binding sites of MBNL2 in control, DM type 1 (DM1), and DM type 2 (DM2) autopsy-derived brain (n=3). Two regions of the brain selected for the study included the frontal cortex and hippocampus. Libraries were sequenced and wiggle files were generated for each biological replicate as well as three pooled biological replicates (3BRs) per group (control, DM1, and DM2). In addition, differential CLIP analysis (dCLIP) was performed to normalize binding data between groups and identify statistically significant changes in binding. The dCLIP analysis generated bedgraph files representing normalized binding profiles of MBNL2 in each group (control, DM1, and DM2) for visualization and comparative analysis. PolyA-seq was performed on control, DM1, and DM2 autopsy-derived brain samples (hippocampus and frontal cortex, n=3) as well as wild-type (WT) and Mbnl1; Mbnl2 conditional double knockout (Mbnl1-/-; Mbnl2c/c; Nestin-Cre+/- or DKO) brain (n=3). Libraries were sequenced and the resultant files were processed and aligned to the reference genomes (hg19 and mm10). Further computational processing was performed to remove internal oligo(dT) mis-priming events, identify valid polyA sites, and trim to the exact polyA sites. BedGraph files were generated for each group in human (control, DM1, and DM2) and mouse (WT and Mbnl DKO) for comparative visualization.
2015-07-30 | E-GEOD-68890 | biostudies-arrayexpress