MBNL Sequestration by Toxic RNAs and RNA Mis-Processing in the Myotonic Dystrophy Brain
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus Homo sapiens
PROVIDER: GSE68890 | GEO | 2015/07/30
SECONDARY ACCESSION(S): PRJNA283977
REPOSITORIES: GEO
Similar Datasets
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
Project description:Myotonic dystrophy (DM) is a multi-systemic disease that severely impacts cardiac and skeletal muscle functions as well as the central nervous system. DM is unusual because it is RNA-mediated disease due to the expression of C(C)UG expansion RNAs that inhibit the activities of the muscleblind-like (MBNL) proteins. In mice, studies using Mbnl1 and Mbnl2 single knockouts have revealed that Mbnl1 plays a predominant role in skeletal and heart muscle alternative splicing regulation while Mbnl2 performs an analogous splicing function in the brain. However, Mbnl single knockout models fail to recapitulate the full-range of adult-onset DM muscle symptoms. Here, we report that Mbnl1; Mbnl2 double knockouts are embryonic lethal while Mbnl1-/-; Mbnl2+/- mice, which express no Mbnl1 and reduced levels of Mbnl2, are viable but develop cardinal features of adult-onset DM cardiac and skeletal muscle disease including reduced lifespan, heart conduction block, severe myotonia and progressive skeletal muscle weakness. Mbnl2 protein levels are elevated in both Mbnl1-/- and Mbnl1-/-; Mbnl2+/- knockouts where Mbnl2 targets Mbnl1-regulated exons. These findings support the MBNL loss-of-function model for DM and provide novel Mbnl compound knockout models to investigate the molecular pathways disrupted by RNA-mediated disease. Mbnl2 protein-RNA interactions were assessed in 4-month-old WT and Mbnl1-/- quadriceps muscles in triplicates by HITS-CLIP.
2013-12-01 | E-GEOD-47794 | biostudies-arrayexpress
Project description:Myotonic dystrophy (DM) is a multi-systemic disease that severely impacts cardiac and skeletal muscle functions as well as the central nervous system. DM is unusual because it is RNA-mediated disease due to the expression of C(C)UG expansion RNAs that inhibit the activities of the muscleblind-like (MBNL) proteins. In mice, studies using Mbnl1 and Mbnl2 single knockouts have revealed that Mbnl1 plays a predominant role in skeletal and heart muscle alternative splicing regulation while Mbnl2 performs an analogous splicing function in the brain. However, Mbnl single knockout models fail to recapitulate the full-range of adult-onset DM muscle symptoms. Here, we report that Mbnl1; Mbnl2 double knockouts are embryonic lethal while Mbnl1-/-; Mbnl2+/- mice, which express no Mbnl1 and reduced levels of Mbnl2, are viable but develop cardinal features of adult-onset DM cardiac and skeletal muscle disease including reduced lifespan, heart conduction block, severe myotonia and progressive skeletal muscle weakness. Mbnl2 protein levels are elevated in both Mbnl1-/- and Mbnl1-/-; Mbnl2+/- knockouts where Mbnl2 targets Mbnl1-regulated exons. These findings support the MBNL loss-of-function model for DM and provide novel Mbnl compound knockout models to investigate the molecular pathways disrupted by RNA-mediated disease.
2013-12-01 | GSE47794 | 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:The Muscleblind-like (Mbnl) family of RNA-binding proteins plays important roles in muscle and eye development and in Myotonic Dystrophy (DM), where expanded CUG or CCUG repeats functionally deplete Mbnl proteins. We identified transcriptome-wide functional and biophysical targets of Mbnl proteins in brain, heart, muscle, and myoblasts using RNA sequencing and crosslinking/immunoprecipitation-sequencing approaches. This analysis identified several hundred splicing events whose regulation depended on Mbnl function, in a pattern indicative of functional interchangeability between Mbnl1 and Mbnl2. A nucleotide resolution RNA map associated repression or activation of exon splicing with Mbnl binding near either 3' splice site or near the downstream 5' splice site, respectively. Transcriptomic analysis of sub-cellular compartments uncovered a global role for Mbnls in regulating localization of mRNAs encoding membrane, synaptic and other proteins in both mouse and Drosophila cells, and Mbnls also contribute to protein secretion. These findings hold several new implications for DM pathogenesis. To assess global functions of Muscleblind proteins, RNA-Seq was performed using WT and Mbnl1 KO brain, heart, and muscle (5 mice each). Additionally, C2C12 mouse myoblasts were depleted of Mbnl1, Mbnl2, or both. Subcellular fractionation experiments were performed to analyze mRNA localization following depletion of Mbnl1 and Mbnl2 in C2C12 mouse myoblasts, and following depletion of Mbnl in Drosophila S-2R+ cells. CLIP-Seq was also performed against Mbnl1 in mouse brain, heart, muscle, and C2C12 myoblasts. Finally, ribosome footprinting was performed with C2C12 mouse myoblasts that were depleted of Mbnl1, Mbnl2, or both.
2012-08-17 | E-GEOD-39911 | biostudies-arrayexpress
Project description:The Muscleblind-like (Mbnl) family of RNA-binding proteins plays important roles in muscle and eye development and in Myotonic Dystrophy (DM), where expanded CUG or CCUG repeats functionally deplete Mbnl proteins. We identified transcriptome-wide functional and biophysical targets of Mbnl proteins in brain, heart, muscle, and myoblasts using RNA sequencing and crosslinking/immunoprecipitation-sequencing approaches. This analysis identified several hundred splicing events whose regulation depended on Mbnl function, in a pattern indicative of functional interchangeability between Mbnl1 and Mbnl2. A nucleotide resolution RNA map associated repression or activation of exon splicing with Mbnl binding near either 3' splice site or near the downstream 5' splice site, respectively. Transcriptomic analysis of sub-cellular compartments uncovered a global role for Mbnls in regulating localization of mRNAs encoding membrane, synaptic and other proteins in both mouse and Drosophila cells, and Mbnls also contribute to protein secretion. These findings hold several new implications for DM pathogenesis.
2012-08-17 | GSE39911 | GEO
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:Myotonic dystrophy (DM) is the most common autosomal dominant muscular dystrophy and encompasses both skeletal muscle and cardiac complications. Myotonic dystrophy is nucleotide repeat expansion disorder in which type 1 (DM1) is due to a trinucleotide repeat expansion on chromosome 19 and type 2 (DM2) arises from a tetranucleotide repeat expansion on chromosome 3. Developing representative models of myotonic dystrophy in animals has been challenging due to instability of nucleotide repeat expansions, especially for DM2 which is characterized by nucleotide repeat expansions often greater than 5000 copies. To investigate mechanisms of human DM, we generated cellular models of DM1 and DM2. We used regulated MyoD expression to reprogram urine-derived cells into myotubes. In this cell model, we found impaired dystrophin expression, MBNL foci, and aberrant splicing in DM1 but not in DM2 cells. We generated induced pluripotent stem cells (iPSC) from healthy controls, DM1 and DM2 subjects and differentiated these into cardiomyocytes. DM1 and DM2 cells displayed an increase in RNA foci concomitant with cellular differentiation. IPSC-derived cardiomyocytes from DM1 but not DM2 had aberrant splicing and MBNL sequestration. High resolution imaging revealed tight association between MBNL clusters and RNA FISH foci in DM1. Ca2+ transients differed between DM1 and DM2 IPSC-derived cardiomyocytes and from healthy control cells. RNA-sequencing from DM1 and DM2 iPSC-derived cardiomyocytes both altered gene expression as well as distinct splicing patterns as differential between DM1 and DM2. Together these data support that DM1 and DM2, despite some shared clinical and molecular features, have distinct pathological signatures.
2019-02-12 | GSE125638 | GEO
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
2014-09-05 | GSE60487 | GEO
Project description:Muscleblind-like proteins (MBNLs) regulate various RNA-processing steps, including alternative splicing, polyadenylation, RNA stability, and mRNA intracellular localization. In myotonic dystrophy type 1 (DM1), the most common muscular dystrophy in adults, MBNLs are sequestered on toxic RNA containing expanded CUG repeats, which leads to disruption of MBNL-regulated processes and disease features of DM1. Herein, we showed the significance of MBNLs in the regulation of microtranscriptome dynamics during postnatal development of skeletal muscles and in microRNA (miRNA) misregulation observed in mouse models and patients with DM1. We identified multiple miRNAs sensitive to insufficiency of MBNL proteins and revealed that many of them were postnatally regulated, which was correlated with increases in the activity of these proteins during this process. In adult Mbnl1-knockout mice, miRNA expression exhibited an adult-to-newborn shift. We identified two mechanisms through which MBNLs influence miRNA levels. First, MBNL loss induces transcriptional changes in miRNA precursors. Second, MBNLs affect miRNA biogenesis by regulating the alternative splicing of miRNA primary transcripts. We propose that the expression of miR-23b, miR-27b and miR-24-1, produced from the same cluster, depends on the MBNL-sensitive inclusion of alternative exons containing miRNA sequences. Our findings suggest that MBNL sequestration in DM1 is partially responsible for altered miRNA activity. This study provides new insights into the biological roles and functions of MBNL proteins as regulators of miRNA expression in skeletal muscles.
2024-08-22 | GSE245814 | GEO