Similar Datasets
Project description:The loss of Muscleblind-like (MBNL) protein function, resulting from its sequestration by toxic CUG-expanded DMPK transcripts, is a central pathological mechanism in myotonic dystrophy type 1 (DM1). However, the role of MBNL in neurodevelopmental disorders associated with severe forms of DM1 remains poorly understood. We used enhanced crosslinking and immunoprecipitation (eCLIP) to study MBNL2-RNA binding sites in 70-day-old forebrain organoids derived from an apparently healthy individual, a patient with congenital myotonic dystrophy (CDM) carrying approximately 2,000 CTG repeats, and an isogenic control in which the pathogenic repeat expansion had been removed. Using Skipper, a workflow allowing improved discovery of protein–RNA binding sites, including in annotated repetitive elements, we identified reproducible enriched windows for the DMPK 3′ UTR in CDM organoids compared to the corresponding input controls. In contrast, no significant binding in the same region was detected in either the unaffected or the isogenic control. This finding supports a physical interaction between MBNL2 and the CUG-expanded DMPK mRNA, observed specifically in neural stem cells of late-stage forebrain organoids by immunostaining and fluorescence in situ hybridization (FISH). Our study highlights the sensitivity of neural stem cells to MBNL2 sequestration during cortical development.
2026-03-12 | GSE315026 | GEO
Project description:The loss of Muscleblind-like (MBNL) protein function, resulting from its sequestration by toxic CUG-expanded DMPK transcripts, is a central pathological mechanism in myotonic dystrophy type 1 (DM1). However, the role of MBNL in neurodevelopmental disorders associated with severe forms of DM1 remains poorly understood. We performed single-cell RNA sequencing using the 10x Genomics Chromium platform to investigate the cellular composition and transcriptomic alterations in forebrain organoids derived from an unaffected individual, a patient with congenital myotonic dystrophy (CDM) carrying approximately 2,000 CTG repeats or an isogenic control in which the pathogenic repeat expansion was removed. Our analysis revealed that MBNL2, known to play a key role in the pathogenesis of myotonic dystrophy, is expressed in a subset of neural stem cells in mature forebrain organoids. We identified altered expression of genes involved in neuronal migration and axonal projection specifically in upper-layer cortical neurons of CDM organoids when compared with both the isogenic and the unaffected control. These findings suggest a role for MBNL2 during prenatal cortical development and highlight impaired differentiation of late-born neurons as a potential contributor to the neurodevelopmental abnormalities associated with CDM.
2026-03-12 | GSE315443 | GEO
Project description:MBNL2 dysfunction in outer radial glial cells is associated with disrupted corticogenesis in congenital myotonic dystrophy
| PRJNA1414420 | ENA
Project description:MBNL2 dysfunction in outer radial glial cells is associated with disrupted corticogenesis in congenital myotonic dystrophy [eCLIP]
| PRJNA1394895 | ENA
Project description:MBNL2 dysfunction in outer radial glial cells is associated with disrupted corticogenesis in congenital myotonic dystrophy [scRNA-Seq]
| PRJNA1397161 | ENA
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 re-expression of 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. We identify prominent alternative splicing and polyadenylation abnormalities in infant CDM muscle, and, although most are also misregulated in adult-onset DM1, dysregulation is significantly more severe in CDM. Furthermore, analysis of alternative splicing during human myogenesis reveals that CDM-relevant exons undergo prenatal RNA isoform transitions and are predicted to be disrupted by CUGexp-associated mechanisms in utero. To test this possibility and the contribution of MBNLs to CDM pathogenesis, 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 that RNA misprocessing is a major pathogenic factor in CDM and provides novel mouse models to further examine roles for cotranscriptional/post-transcriptional gene regulation during development.
| S-EPMC5538435 | 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 (DM) is caused by expansions of C(C)TG repeats in the non-coding regions of the DMPK and CNBP genes, and DM patients often suffer from sudden cardiac death due to lethal conduction block or 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 (CELF1). Hypothesis solely targeting MBNL1 or CELF1 pathways that could address all the consequences of repeat expansion in heart remained inconclusive, particularly when the direct cause of mortality and results of transcriptome analyses remained undetermined in Mbnl compound knockout (KO) mice with cardiac phenotypes. Here, we develop Myh6-Cre double KO (DKO) (Mbnl1-/-; Mbnl2cond/cond; Myh6-Cre+/-) mice to eliminate Mbnl1/2 in cardiomyocytes and observe spontaneous lethal cardiac events under no anesthesia. RNA sequencing recapitulates DM heart spliceopathy and shows gene expression changes that were previously undescribed in DM heart studies. Notably, immunoblotting reveals a nearly 6-fold increase of Calsequestrin 1 and 50% reduction of epidermal growth factor proteins. Our findings demonstrate that complete ablation of MBNL1/2 in cardiomyocytes is essential for generating sudden death due to lethal cardiac rhythms and reveal potential mechanisms for DM heart pathogenesis.
| S-EPMC9476621 | biostudies-literature
Project description:Myotonic dystrophy types 1 (DM1) and 2 (DM2) are dominantly inherited neuromuscular disorders caused by a toxic gain of function of expanded CUG and CCUG repeats, respectively. Although both disorders are clinically similar, congenital myotonic dystrophy (CDM), a severe DM form, is found only in DM1. CDM is also characterized by muscle fiber immaturity not observed in adult DM, suggesting specific pathological mechanisms. Here, we revealed upregulation of the interleukin-6 (IL-6) myokine signaling pathway in CDM muscles. We also found a correlation between muscle immaturity and not only IL-6 expression but also expanded CTG repeat length and CpG methylation status upstream of the repeats. Aberrant CpG methylation was associated with transcriptional dysregulation at the repeat locus, increasing the toxic RNA burden that upregulates IL-6. Because the IL-6 pathway is involved in myocyte maturation and muscle atrophy, our results indicate that enhanced RNA toxicity contributes to severe CDM phenotypes through aberrant IL-6 signaling.
| S-EPMC5689469 | biostudies-literature
Project description:Disrupted prenatal RNA processing and myogenesis in congenital myotonic dystrophy
| PRJNA382960 | ENA