Deregulation of the ubiquitin-proteasome system is the predominant molecular pathology in OPMD animal models and patients
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE26605 | GEO | 2011/04/19
SECONDARY ACCESSION(S): PRJNA136213
REPOSITORIES: GEO
Similar Datasets
Project description:Oculopharyngeal muscular dystrophy (OPMD) is an adult-onset syndrome characterized by progressive degeneration of particular muscles. OPMD is caused by short GCG 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 created a Drosophila model of OPMD that recapitulates the features of the human disorder: progressive muscle degeneration, with muscle defects proportional to the number of alanines in the tract, and formation of PABPN1 nuclear inclusions. Wild-type human PABPN1 contains a stretch of 10 alanines following the initial methionine, which is expanded to 12–17 alanines in OPMD patients. In Drosophila, the PABPN1 homolog is the poly(A)-binding protein 2 (PABP2), which has the same function as PABPN1 in nuclear polyadenylation but lacks a polyalanine tract at the N-terminus. We used the UAS/Gal4 system to express mammalian PABPN1 in Drosophila. An alanine-expanded PABPN1 cDNA (encoding the 17 alanine tract) was cloned downstream of UAS sequences (UAS-PABPN1). Transgenic lines containing this construct were crossed to a Mhc-Gal4 driver, leading to muscle-specific expression. To gain insight into the molecular and physiological defects in OPMD we performed a transcriptomic analysis in OPMD fly muscles. Using microarrays, thorax gene expression was compared between control flies (Mhc-Gal4/+) and flies expressing PABPN1-17ala in thoracic muscles (UAS-PABPN1-17ala/+; Mhc-Gal4/+), at three time points (days 2, 6 and 11). Transcriptome of thorax RNA samples from control (Mhc-Gal4/+) flies and flies expressing PABPN1-17ala (UAS-PABPN1-17ala/+; Mhc-Gal4/+)
2014-12-12 | GSE64094 | 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 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 disorder characterized by ptosis, dysphagia and proximal limb weakness. Autosomal-dominant OPMD is caused by a short (GCG)8–13 expansions within the first exon of the poly(A)-binding protein nuclear 1 gene (PABPN1), leading to an expanded polyalanine tract in the mutated protein. Expanded PABPN1 forms insoluble aggregates in the nuclei of skeletal muscle fibres. In order to gain insight into the different physiological processes affected in OPMD muscles, we have used a transgenic mouse model of OPMD (A17.1) and performed transcriptomic studies combined with a detailed phenotypic characterization of this model at three time points. The transcriptomic analysis revealed a massive gene deregulation in the A17.1 mice, among which we identified a significant deregulation of pathways associated with muscle atrophy. Using a mathematical model for progression, we have identified that one-third of the progressive genes were also associated with muscle atrophy. Functional and histological analysis of the skeletal muscle of this mouse model confirmed a severe and progressive muscular atrophy associated with a reduction in muscle strength. Moreover, muscle atrophy in the A17.1 mice was restricted to fast glycolytic fibres, containing a large number of intranuclear inclusions (INIs). The soleus muscle and, in particular, oxidative fibres were spared, even though they contained INIs albeit to a lesser degree. These results demonstrate a fibre-type specificity of muscle atrophy in this OPMD model. This study improves our understanding of the biological pathways modified in OPMD to identify potential biomarkers and new therapeutic targets.
2011-01-14 | GSE26604 | GEO
Project description:Oculopharyngeal muscular dystrophy (OPMD) is an adult-onset disorder characterized by ptosis, dysphagia and proximal limb weakness. Autosomal-dominant OPMD is caused by a short (GCG)8–13 expansions within the first exon of the poly(A)-binding protein nuclear 1 gene (PABPN1), leading to an expanded polyalanine tract in the mutated protein. Expanded PABPN1 forms insoluble aggregates in the nuclei of skeletal muscle fibres. In order to gain insight into the different physiological processes affected in OPMD muscles, we have used a transgenic mouse model of OPMD (A17.1) and performed transcriptomic studies combined with a detailed phenotypic characterization of this model at three time points. The transcriptomic analysis revealed a massive gene deregulation in the A17.1 mice, among which we identified a significant deregulation of pathways associated with muscle atrophy. Using a mathematical model for progression, we have identified that one-third of the progressive genes were also associated with muscle atrophy. Functional and histological analysis of the skeletal muscle of this mouse model confirmed a severe and progressive muscular atrophy associated with a reduction in muscle strength. Moreover, muscle atrophy in the A17.1 mice was restricted to fast glycolytic fibres, containing a large number of intranuclear inclusions (INIs). The soleus muscle and, in particular, oxidative fibres were spared, even though they contained INIs albeit to a lesser degree. These results demonstrate a fibre-type specificity of muscle atrophy in this OPMD model. This study improves our understanding of the biological pathways modified in OPMD to identify potential biomarkers and new therapeutic targets. A17.1 transgenic mice have previously been described. Male A17.1 mice and WT controls were generated by crossing the heterozygous carrier strain A17.1 obtained from Rubinsztein's group with the FvB background mice. The mice were genotyped by PCR 3–4 weeks after birth. Wild type FvB and A17.1 mice were housed in minimal disease facilities (Royal Holloway, University of London) with food and water ad libitum. Total RNA was extracted from skeletal muscles using RNA Bee (Amsbio) according to the manufacturer's instructions. RNA integration number (RIN) was determined with RNA 6000 Nano (Agilent Technologies). RNA with RIN >7 were used for subsequent steps. RNA labelling was performed with the Illumina® TotalPrep RNA Amplification kit (Ambion) according to the manufacturer's protocol, and subsequently was hybridized to Illumina Mouse v1.1 Bead arrays.
2011-01-14 | E-GEOD-26604 | biostudies-arrayexpress
Project description:Poly(A) binding protein nuclear 1 (PABPN1) is a multifunctional regulator of mRNA processing. PABPN1 inhibits alternative polyadenylation (APA), and in conditions with reduced PABPN1 levels APA utilization causes genome-wide mRNA dysregulation. PABPN1 levels decline from midlife onwards in Oculopharyngeal Muscular Dystrophy (OPMD) and in aged muscles. Reduced PABPN1 levels cause muscle atrophy by altering mRNA levels of the ubiquitin proteasome system. The effect of PABPN1-mediated APA utilization on the proteome has not been investigated yet. We report the PABPN1-mediated proteome in Tibialis anterior (TA) mouse muscles, signifying functional impact for the mitochondria, cytoskeleton and translation cellular machineries. Central nucleation and split myofibers marked PABPN1-derived muscle histology. We show that up-regulation of the cytoskeletal proteins: Murc, Pfn1 and Csrp3, is highly associated with PABPN1-mediated muscle pathology and with reduced PABPN1 levels. Elevation of PABPN1 levels by sirtinol treatment reversed muscle pathology and restored levels of those cytoskeletal proteins. We suggest that restoration of PABPN1 levels in aged muscles could be a novel therapeutic strategy to mitigate muscle waste.
2020-07-06 | PXD004865 | Pride
Project description:The ubiquitin-proteasome and autophagy-lysosome pathways are the two major routes for protein and organelle clearance. In skeletal muscle, both systems’ excessive activation induces severe muscle loss. Although altered proteasomal function has been observed in various myopathies, the specific role of proteasomal activity in skeletal muscle has not been determined by loss-of-function approaches. Here, we report that muscle-specific deletion of a crucial proteasomal gene, Rpt3, resulted in profound muscle atrophy and decrease in force. Rpt3 null muscles showed reduced proteasomal activity in early age, accumulation of basophilic structure, disorganization of sarcomere, and formation of vacuoles and concentric membranous structures in electronmicroscope. We also observed accumulation of ubiquitin, p62, LC3, TDP43, FUS and VCP proteins. Proteasomal activity is important to preserve muscle mass and to maintain myofiber integrity. Our results suggest that inhibition/alteration of proteasomal activity can contribute to myofiber degeneration and weakness in muscle disorders, such as inclusion body myositis, characterized by accumulation of abnormal inclusions. Tibialis anterior muscles from Rpt3 null and control mice. each 3 mice.
2014-09-30 | E-GEOD-34896 | biostudies-arrayexpress
Project description:Reduced PABPN1 levels cause aging-associated muscle wasting. PABPN1 is a multi-functional regulator of mRNA processing. To elucidate the molecular mechanisms causing PABPN1-mediated muscle wasting, we compared the transcriptome to the proteome in mouse muscles expressing shRNA to PABPN1 (shPab). We found greater variations in the proteome as compared to mRNA expression profiles. Protein accumulation in the shPab proteome was concomitant with reduced proteasomal activity. Notably, protein acetylation appeared to be enriched in shPab versus control proteomes (63%). An acetylome study in shPab muscles revealed prominent peptide deacetylation associated with elevated sirtuin-1 (SIRT1) deacetylase. We show that SIRT1 mRNA levels are controlled by PABPN1 via an alternative polyadenylation site utilization. SIRT1 inhibition reversed PABPN1 activity and muscle cell function. Moreover, deacetylation inhibition increased PABPN1 levels and reversed muscle wasting. We suggest that perturbation of a multifactorial regulatory loop involving PABPN1 and SIRT1 plays an imperative role in aging-associated muscle wasting.
2022-02-28 | PXD011534 | Pride
Project description:Modeling OPMD in myotube cultures reveals reduced accumulation of soluble mutant PABPN1 protein
| PRJNA140821 | ENA