Nuclear Protein Aggregates Disrupt RNA Processing and Alter Biomechanics in a Muscle Cell Model of OPMD
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE277571 | GEO | 2025/09/09
REPOSITORIES: GEO
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Project description:Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant disease caused by an alanine tract expansion mutation in Poly(A)-binding protein nuclear 1 (expPABPN1). To model OPMD in a myogenic and physiological context, we generated mouse myoblast cell clones stably expressing either human wild type (WT) or expPABPN1 at low levels. The transgene expression is induced upon myotube differentiation and results in formation of insoluble nuclear PABPN1 aggregates that are similar to the in vivo aggregates. Quantitative analysis of PABPN1 protein in myotube cultures revealed that expPABPN1 accumulation and aggregation is greater than that of the WT protein. In a comparative study we found that aggregation of expPABPN1 is more affected by inhibition of proteasome activity, as compared with the WT PABPN1 aggregation. Consistent with this, in myotubes cultures expressing expPABPN1 deregulation of the proteasome was identified as the most significantly deregulated pathway. Differences in the accumulation of soluble WT and expPABPN1 were consistent with differences in ubiquitination and protein turnover. This study indicates, for the first time, that in myotubes the ratio of soluble to insoluble expPABPN1 is significantly lower compared to that of the WT protein. We suggest that this difference can contribute to muscle weakness in OPMD. Clones on IM2 mouse myotubes that stably express Ala10-PABPN1-FLAG (WTA, WTD) or Ala17-PABPN1-FLAG (D7E). The transgene expression level in D7E and WTA are similar. WTA and WTD reflects differences in expression levels. RNA was extracted from myotubes of WTA, WTD and D7E in triplicates. cDNA synthesis and lebeling was preformed with the Illumina cDNA labeling kit.
2011-08-31 | E-GEOD-29909 | biostudies-arrayexpress
Project description:Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant disease caused by an alanine tract expansion mutation in Poly(A)-binding protein nuclear 1 (expPABPN1). To model OPMD in a myogenic and physiological context, we generated mouse myoblast cell clones stably expressing either human wild type (WT) or expPABPN1 at low levels. The transgene expression is induced upon myotube differentiation and results in formation of insoluble nuclear PABPN1 aggregates that are similar to the in vivo aggregates. Quantitative analysis of PABPN1 protein in myotube cultures revealed that expPABPN1 accumulation and aggregation is greater than that of the WT protein. In a comparative study we found that aggregation of expPABPN1 is more affected by inhibition of proteasome activity, as compared with the WT PABPN1 aggregation. Consistent with this, in myotubes cultures expressing expPABPN1 deregulation of the proteasome was identified as the most significantly deregulated pathway. Differences in the accumulation of soluble WT and expPABPN1 were consistent with differences in ubiquitination and protein turnover. This study indicates, for the first time, that in myotubes the ratio of soluble to insoluble expPABPN1 is significantly lower compared to that of the WT protein. We suggest that this difference can contribute to muscle weakness in OPMD. Clones on IM2 mouse myotubes that stably express Ala10-PABPN1-FLAG (WTA, WTD) or Ala17-PABPN1-FLAG (D7E). The transgene expression level in D7E and WTA are similar. WTA and WTD reflects differences in expression levels.
2011-09-01 | GSE29909 | GEO
Project description:Oculopharyngeal muscular dystrophy (OPMD) is an adult-onset syndrome characterized by progressive degeneration of specific muscles. OPMD is caused by short GCN repeat expansions within the gene encoding the nuclear poly(A)-binding protein 1 (PABPN1) that extend an N-terminal polyalanine tract in the protein. Mutant PABPN1 aggregates as nuclear inclusions in OMPD patient muscles. We have used the transgenic mouse A17.1 OPMD model that recapitulates the features of the human disorder: progressive muscle weakness, atrophy and formation of PABPN1 nuclear inclusions. Wild-type human PABPN1 contains a stretch of 10 alanines following the initial methionine, which is expanded to 11–18 alanines in OPMD patients. Transgenic A17.1 mouse overexpress an 17 alanine expanded PABPN1 under the control of the HSA promoter. To evaluate a gene therapy approach based on AAV delivery of a ‘suppress and replace’ strategy in OPMD we performed a transcriptomic analysis in treated muscles 18 weeks after injection. Using microarrays, tibialis anterior gene expression was compared between control muscles (FvB), OPMD muscles (A17), AAV-shRNA3x treated muscles (A17 shRNA3X), AAVoptPABPN1 treated muscles (A17 optPABPN1), and AAV-shRNA3x+AAV-optPABPN1 treated muscles (A17 dual).
2017-06-12 | GSE89996 | GEO
Project description:Oculopharyngeal muscular dystrophy (OPMD) is a late-onset progressive muscle disorder caused by a poly-alanine expansion mutation in PABPN1. The hallmark of OPMD is the accumulation of the mutant protein in insoluble nuclear inclusions. The molecular mechanisms associated with disease onset and progression are unknown. We performed a high-throughput cross-species transcriptome study of affected muscles from two OPMD animal models and from patients at pre-symptomatic and symptomatic stages. The most consistently and significantly OPMD-deregulated pathway across species is the ubiquitin-proteasome system (UPS). By analyzing expression profiles, we found that the majority of OPMD-deregulated genes are age-associated. Based on expression trends, disease onset can be separated from progression; the expression profiles of the proteasome-encoding genes are associated with onset but not with progression. In a muscle cell model, proteasome inhibition and the stimulation of immunoproteasome specifically affect the accumulation and aggregation of mutant PABPN1. We suggest that proteasome down-regulation during muscle aging triggers the accumulation of expPABPN1 that in turn enhances proteasome deregulation and leads to intranuclear inclusions (INI) formation.
2011-04-19 | GSE26605 | GEO
Project description:The tongue facilitates vital activities such as swallowing. Swallowing difficulties (dysphagia) are common in the elderly and in many adult-onset neuromuscular diseases. In oculopharyngeal muscular dystrophy (OPMD), dysphagia is often the first symptom. OPMD is an autosomal dominant myopathy caused by a trinucleotide expansion mutation in the gene encoding PABPN1. The expanded PABPN1 forms insoluble nuclear aggregates that reduce the levels of the soluble form. Clinical tongue involvement in OPMD has been documented but is poorly understood. Tongue histopathology was investigated in OPMD mouse models using light and electron microscopy. Muscle histopathology was predominantly affected by age. PABPN1 nuclear aggregates were found at moderate levels, whereas deposition of insoluble PABPN1 in blood vessels was already prominent in 4-month-old mice. RNA signatures of the OPMD tongue were enriched for mitochondrial and cytoskeletal genes, suggesting an energy and contractile deficit.
2024-12-04 | GSE263433 | GEO
Project description:Nuclear Protein Aggregates Disrupt RNA Processing and Alter Biomechanics in a Muscle Cell Model of OPMD
| PRJNA1162837 | ENA
Project description:Among the many factors influencing fibrin formation and structure (concentration, temperature, composition, pH, etc.), it has been suggested that the polydispersity of fibrinogen may play an important role. We propose here a detailed investigation of the influence of this parameter on fibrin multiscale structure. Two commercial fibrinogen preparations were used, a monodisperse and a polydisperse one. First, the respective compositions of both fibrinogen preparations were thoroughly determined by measuring the fibrin-stabilizing factor; fibronectin; α, β, and γ intact chain contents; the γ/γ' chains ratio; the N-glycosylation; and the post-translational modifications. Slight variations between the composition of the two fibrinogen preparations were found that are much smaller than the compositional variations necessary to alter significantly fibrin multiscale structure as observed in the literature. Conversely, multiangle laser light scattering-coupled size exclusion chromatography and dynamic light scattering measurements showed that the polydisperse preparation contains significant amounts of aggregates, whereas the other preparation is essentially monodisperse. The multiscale structure of the fibrins produced from those two fibrinogen preparations was determined by using x-ray scattering, spectrophotometry, and confocal microscopy. Results show that fibers made from the aggregate-free fibrinogen present a crystalline longitudinal and lateral structure and form a mikado-like network. The network produced from the aggregates containing fibrinogen looks to be partly built around bright spots that are attributed to the aggregate. The multiscale structure of mixtures between the two preparations shows a smooth evolution, demonstrating that the quantity of aggregates is a major determining factor for fibrin multiscale structure. Indeed, the effect of a few percent in the mass of aggregates is larger than any other effect because of compositional differences under the same reaction conditions. Finally, we propose a mechanistic interpretation of our results, which points at a direct role of the aggregates during polymerization, which disrupts the ideal ordering of monomers inside fibrin protofibrils and fibers.
| S-EPMC6950636 | biostudies-literature
Project description:The lack of tools to identify causative variants from sequencing data greatly limits the promise of precision medicine. Previous studies suggest that one-third of disease-associated alleles alter splicing. We discovered that the alleles causing splicing defects cluster in disease-associated genes (for example, haploinsufficient genes). We analyzed 4,964 published disease-causing exonic mutations using a massively parallel splicing assay (MaPSy), which showed an 81% concordance rate with splicing in patient tissue. Approximately 10% of exonic mutations altered splicing, mostly by disrupting multiple stages of spliceosome assembly. We present a large-scale characterization of exonic splicing mutations using a new technology that facilitates variant classification and keeps pace with variant discovery.
| S-EPMC6679692 | biostudies-literature
Project description:stable transfected cell lines IM2 = untransfected WTA = wildtype pabpn1 transfected high WTD = wildtype pabpn1 transfected low D7E = mutant pabpn1 transfected high D7F = mutant pabpn1 transfected low 5 cell lines triplicate cultures dye-swap
2006-04-20 | E-GEOD-2734 | biostudies-arrayexpress
Project description:The polyadenosine RNA binding proteins (Pabs) represent one class of RNA binding proteins that play critical roles in gene expression. This class includes the well-studied nuclear and cytoplasmic Pabs, PABPN1 and PABPC1, respectively, as well as the newly characterized nuclear Pab, zinc finger CCCH-type containing #14, or ZC3H14. ZC3H14 was recently linked to a form of intellectual disability, suggesting a critical role for ZC3H14 in neurons; however, the post-transcriptional function of ZC3H14 is unknown. In this study, we performed a microarray analysis of cells depleted of ZC3H14 or PABPN1 in MCF-7 breast cancer cells. These results revealed that PABPN1 significantly affected ~17% of expressed transcripts as compared to ZC3H14, which affected ~1% of expressed transcripts, suggesting that ZC3H14 has specific mRNA targets. The differentially expressed mRNAs identified in this analysis not only provide information about the classes and types of transcripts that are regulated by these proteins, but also represent a set of transcripts that could be directly bound by ZC3H14 and/or PABPN1. Total RNA isolated from MCF-7 cells treated for 48 hours with siRNA targeting PABPN1, ZC3H14 (all splice variants), or a control scramble siRNA.
2014-10-06 | E-GEOD-62067 | biostudies-arrayexpress