MBNL Sequestration by Toxic RNAs and RNA Mis-Processing in the Myotonic Dystrophy Brain
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA283977 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR2026300.fastq.gz | Fastqsanger.gz | |||
| SRR2026310.fastq.gz | Fastqsanger.gz | |||
| SRR2026320.fastq.gz | Fastqsanger.gz | |||
| SRR2026330.fastq.gz | Fastqsanger.gz | |||
| SRR2026301.fastq.gz | Fastqsanger.gz |
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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: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.
2015-07-30 | GSE68890 | GEO
Project description:Myotonic dystrophy type 1 is a dominantly inherited multisystemic disease caused by CTG tandem repeat expansions in the DMPK 3' untranslated region. These expanded repeats are transcribed and produce toxic CUG RNAs that sequester and inhibit activities of the MBNL family of developmental RNA processing factors. Although myotonic dystrophy is classified as a muscular dystrophy, the brain is also severely affected by an unusual cohort of symptoms, including hypersomnia, executive dysfunction, as well as early onsets of tau/MAPT pathology and cerebral atrophy. To address the molecular and cellular events that lead to these pathological outcomes, we recently generated a mouse Dmpk CTG expansion knockin model and identified choroid plexus epithelial cells as particularly affected by the expression of toxic CUG expansion RNAs. To determine if toxic CUG RNAs perturb choroid plexus functions, alternative splicing analysis was performed on lateral and hindbrain choroid plexi from Dmpk CTG knockin mice. Choroid plexus transcriptome-wide changes were evaluated in Mbnl2 knockout mice, a developmental-onset model of myotonic dystrophy brain dysfunction. To determine if transcriptome changes also occurred in the human disease, we obtained post-mortem choroid plexus for RNA-seq from donors without neurologically unaffected (two females, three males; ages 50-70) and myotonic dystrophy type 1 donors (one female, three males; ages 50-70). To test that choroid plexus transcriptome alterations resulted in altered CSF composition, we obtained CSF via lumbar puncture from patients with myotonic dystrophy type 1 (five females, five males; ages 35-55) and non-myotonic dystrophy patients (three females, four males; ages 26-51) and Western blot and osmolarity analyses were used to test CSF alterations predicted by choroid plexus transcriptome analysis. We determined that CUG RNA induced toxicity was more robust in the lateral choroid plexus of Dmpk CTG knockin mice due to comparatively higher Dmpk and lower Mbnl RNA levels. Impaired transitions to adult splicing patterns during choroid plexus development were identified in Mbnl2 knockout mice, including mis-splicing previously found in Dmpk CTG knockin mice. Whole transcriptome analysis of myotonic dystrophy type 1 choroid plexus revealed disease-associated RNA expression and mis-splicing events. Based on these RNA changes, predicted alterations in ion homeostasis, secretory output, and CSF composition were confirmed by analysis of myotonic dystrophy type 1 CSF. Our results implicate choroid plexus spliceopathy and concomitant alterations in CSF homeostasis as an unappreciated contributor to myotonic dystrophy type 1 CNS pathogenesis.
2023-07-03 | GSE228458 | GEO
Project description:Myotonic dystrophy type 1 is a dominantly inherited multisystemic disease caused by CTG tandem repeat expansions in the DMPK 3' untranslated region. These expanded repeats are transcribed and produce toxic CUG RNAs that sequester and inhibit activities of the MBNL family of developmental RNA processing factors. Although myotonic dystrophy is classified as a muscular dystrophy, the brain is also severely affected by an unusual cohort of symptoms, including hypersomnia, executive dysfunction, as well as early onsets of tau/MAPT pathology and cerebral atrophy. To address the molecular and cellular events that lead to these pathological outcomes, we recently generated a mouse Dmpk CTG expansion knockin model and identified choroid plexus epithelial cells as particularly affected by the expression of toxic CUG expansion RNAs. To determine if toxic CUG RNAs perturb choroid plexus functions, alternative splicing analysis was performed on lateral and hindbrain choroid plexi from Dmpk CTG knockin mice. Choroid plexus transcriptome-wide changes were evaluated in Mbnl2 knockout mice, a developmental-onset model of myotonic dystrophy brain dysfunction. To determine if transcriptome changes also occurred in the human disease, we obtained post-mortem choroid plexus for RNA-seq from donors without neurologically unaffected (two females, three males; ages 50-70) and myotonic dystrophy type 1 donors (one female, three males; ages 50-70). To test that choroid plexus transcriptome alterations resulted in altered CSF composition, we obtained CSF via lumbar puncture from patients with myotonic dystrophy type 1 (five females, five males; ages 35-55) and non-myotonic dystrophy patients (three females, four males; ages 26-51) and Western blot and osmolarity analyses were used to test CSF alterations predicted by choroid plexus transcriptome analysis. We determined that CUG RNA induced toxicity was more robust in the lateral choroid plexus of Dmpk CTG knockin mice due to comparatively higher Dmpk and lower Mbnl RNA levels. Impaired transitions to adult splicing patterns during choroid plexus development were identified in Mbnl2 knockout mice, including mis-splicing previously found in Dmpk CTG knockin mice. Whole transcriptome analysis of myotonic dystrophy type 1 choroid plexus revealed disease-associated RNA expression and mis-splicing events. Based on these RNA changes, predicted alterations in ion homeostasis, secretory output, and CSF composition were confirmed by analysis of myotonic dystrophy type 1 CSF. Our results implicate choroid plexus spliceopathy and concomitant alterations in CSF homeostasis as an unappreciated contributor to myotonic dystrophy type 1 CNS pathogenesis.
2023-07-03 | GSE228314 | GEO
Project description:Myotonic Dystrophy Type 1 (DM1) is an autosomal dominant disease caused by a CTG repeat expansion in the DMPK gene. The expanded CUG repeat RNA (CUGexp RNA) transcribed from the mutant allele sequesters the muscleblind-like (MBNL) family of RNA-binding proteins, causing their loss of function and disrupting regulated pre-mRNA processing. We used a DM1 heart mouse model that inducibly expresses CUGexp RNA to test the contribution of MBNL loss to DM1 cardiac abnormalities and explore MBNL restoration as a potential therapy. AAV9-mediated overexpression of MBNL1 and/or MBNL2 significantly rescued DM1 cardiac phenotypes including conduction delays, contractile dysfunction, hypertrophy, and mis-regulated alternative splicing and gene expression. While robust, rescue was partial compared to reduced CUGexp RNA and plateaued with increased exogenous MBNL expression. These findings demonstrate that MBNL loss is a major contributor to DM1 cardiac manifestations, and suggest that additional mechanisms play a role, highlighting the complex nature of DM1 pathogenesis.
2025-03-30 | GSE283998 | 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:For some neurological disorders, disease is primarily RNA mediated due to expression of non-coding microsatellite expansion RNAs (RNA(exp)). 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 RNA(exp) in the DM brain and introduce a powerful experimental tool to evaluate RNA-mediated toxicity in other expansion diseases.
| S-EPMC4545389 | biostudies-literature
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 the most common adult-onset muscular dystrophy and severely affects multiple organ systems, including the brain, heart, skeletal muscle, and gastrointestinal (GI) tract. Despite 80% of individuals with DM1 experiencing GI dysfunction that affects their daily life, the mechanisms of GI dysmotility in DM1 remain an understudied aspect of the disease. DM1 is caused by a CTG repeat expansion in the DMPK gene that, when expressed as an expanded CUG repeat RNA, sequesters and reduces the activity of the muscleblind-like (MBNL) RNA-binding protein family. We developed a mouse line with conditional, smooth muscle-specific knockout of Mbnl1 and Mbnl2 to model and investigate myogenic mechanisms contributing to GI dysmotility in DM1. Mice with Mbnl knockout exhibited delayed GI transit of small and large bowel in vivo and increased smooth muscle contractile tone of jejunum and colon segments ex vivo. Smooth muscle from jejunum and colon showed no histopathologic changes and contained increased phosphorylation of the 20 kDa myosin light chain (Mlc20), consistent with increased contraction. RNA sequencing of mouse and human DM1 GI samples enriched for smooth muscle revealed conserved misregulated alternative splicing of transcripts associated with the regulation of Mlc20 phosphorylation and smooth muscle contraction. These findings demonstrate that Mbnl KO disrupts the regulation of contraction dynamics and causes GI smooth muscle hyperactivity, suggesting that therapeutics that reduce GI contractile activity may help alleviate DM1 GI symptoms.
2025-09-01 | GSE305442 | GEO
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