Gene-expression profiling of SEPN1 knockout or wild type mice injected with either ERO1 or PBS
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
SUBMITTER: MARCO BOLIS
PROVIDER: E-MTAB-4933 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:Maintaining skeletal muscle mass is of high importance as muscle atrophy like during sarcopenia or cachexia lead to a decrease in independence and a higher risk of morbidity and mortality. A leading compound in the treatment against ageing and cancer is rapamycin, an inhibitor of mechanistic target of rapamycin complex 1 (mTORC1). Whether the treatment with mTORC1 inhibitors would work at a cost of losing muscle mass is unclear, as most studies have been focusing on the role of mTORC1 specifically during hypertrophy. In order to answer this question we developed an inducible muscle specific knockout mouse model in which raptor can be ablated during adulthood to eliminate mTORC1 activity. We analysed the muscles after different time points and found that after 3 months the mice showed a fiber shift towards slower fiber types, a loss in oxidative capacity but only very few myopathic features. After 5 months the myopathic features became more apparent, however it did not largely affect the ex vivo muscle force. Surprisingly despite the myopathy we did not see a significant loss of muscle mass even after 5 months, that we hypothesised based on mTORC1s central role in protein synthesis. We assume that the myopathy after long-term mTORC1 inactivation is mostly a result of secondary effects through the loss of mitochondria, alterations in metabolism and in cytoskeletal components. In conclusion, during skeletal muscle maintenance mTORC1 is more essential for metabolic processes than it is for maintaining basal muscle mass.Maintaining skeletal muscle mass is of high importance as muscle atrophy like during sarcopenia or cachexia lead to a decrease in independence and a higher risk of morbidity and mortality. A leading compound in the treatment against ageing and cancer is rapamycin, an inhibitor of mechanistic target of rapamycin complex 1 (mTORC1). Whether the treatment with mTORC1 inhibitors would work at a cost of losing muscle mass is unclear, as most studies have been focusing on the role of mTORC1 specifically during hypertrophy. In order to answer this question we developed an inducible muscle specific knockout mouse model in which raptor can be ablated during adulthood to eliminate mTORC1 activity. We analysed the muscles after different time points and found that after 3 months the mice showed a fiber shift towards slower fiber types, a loss in oxidative capacity but only very few myopathic features. After 5 months the myopathic features became more apparent, however it did not largely affect the ex vivo muscle force. Surprisingly despite the myopathy we did not see a significant loss of muscle mass even after 5 months, that we hypothesised based on mTORC1s central role in protein synthesis. We assume that the myopathy after long-term mTORC1 inactivation is mostly a result of secondary effects through the loss of mitochondria, alterations in metabolism and in cytoskeletal components. In conclusion, during skeletal muscle maintenance mTORC1 is more essential for metabolic processes than it is for maintaining basal muscle mass.
2019-10-14 | PXD013294 | Pride
Project description:Neuromuscular disorders (NMDs) are clinically and genetically heterogenous and manifest as dystrophic, inflammatory and myopathic pathologies, among others. Our previous study on the cardiotoxin (CTX) mouse model of myodegeneration and inflammation linked muscle pathology with mitochondrial damage and oxidative stress. In this study, we investigated whether human NMDs display mitochondrial changes. Muscle biopsies from NMD patients, represented by dystrophic pathology [dysferlinopathy (dysfy); n=43], inflammatory pathology [inflammatory myopathy (IM); n=24] and myopathic pathology [distal myopathy with rimmer vacuoles (DMRV); n=31] were analysed. Mitochondrial damage was revealed in all NMDs by Enzyme histochemistry (SDH and SDH-COX deficiency), electron microscopy (vacuolation and abnormal ultrastructures) and biochemical assays (significantly increased ADP/ATP ratio). Proteomic analysis of muscle mitochondria from all three NMDs by Isobaric tag for relative and absolute quantitation (iTRAQ) labelling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis demonstrated down-regulation of electron transport chain (ETC) complex subunits, assembly factors and Krebs cycle enzymes. Most of the differentially expressed proteins were common among the three pathologies. Assay of ETC and Krebs cycle enzyme activities validated the MS data. Mitochondrial proteins from muscle pathologies also displayed higher trp oxidation and the same was corroborated in the CTX model. Molecular modelling predicted trp oxidation to alter the local structure of mitochondrial proteins. Our data highlight mitochondrial alterations in muscle pathologies, represented by structural changes, altered mitochondrial proteome and protein oxidation status, thereby establishing the importance of mitochondrial damage in human NMDs.
2016-04-04 | PXD002760 | Pride
Project description:Skeletal muscle must perform a wide range of kinds of work, and different fiber types have evolved to accommodate these different tasks. The attributes of fibers are determined in large part by the coordinated regulation of oxidative capacity, as reflected by mitochondrial content, and the specific makeup of myofibrillar proteins. Adult muscle fibers contain four myosin heavy chain isotypes: I, IIa, IIx and IIb. Type I and IIa fibers have slower twitches and are rich in mitochondria, while type IIb fibers are fast-twitch and predominantly glycolytic. The intermediate IIx fibers are less well understood. Previous work had shown that the transcriptional coactivator PGC-1 alpha could drive the formation of type I and IIa muscle fibers. We show here that mice with transgenic expression of PGC-1 beta in skeletal muscle results in marked induction of IIx fibers. The fibers in transgenic mice are rich in mitochondria and are highly oxidative. As a result, PGC-1 beta transgenic animals can perform oxidative activity for longer and at higher work loads than wild type animals. In cell culture, PGC-1 beta coactivates the MEF2 family of transcription factors to stimulate the MHC IIx promoter. Together, these data indicate that PGC-1 beta is sufficient to drive the formation in vivo of highly oxidative fibers with type IIx characteristics.
2007-04-02 | E-MEXP-939 | biostudies-arrayexpress
Project description:Septic patients treated in the intensive care unit (ICU) often develop multiple organ failure including persistent skeletal muscle dysfunction which results in the patientâs protracted recovery process. We have demonstrated that muscle mitochondrial enzyme activities are impaired in septic ICU patients resulting in decreased cellular energy which will interfere with muscle function and metabolism. Here we use detailed phenotyping and genomics to elucidate mechanisms leading to these impairments. Methodology/Principle Findings Utilising biopsy material from seventeen patients and ten age-matched controls we demonstrate that neither mitochondrial in vivo protein synthesis nor expression of mitochondrial genes are compromised. Indeed, there was partial activation of the mitochondrial biogenesis pathway involving NRF2?/GABP and its target genes TFAM, TFB1M and TFB2M yet clearly this failed to maintain mitochondrial function. We therefore utilised transcript profiling and pathway analysis of ICU patient skeletal muscle to generate insight into the molecular defects driving loss of muscle function and metabolic homeostasis. Gene ontology analysis of Affymetrix analysis demonstrated substantial loss of muscle specific genes, a global oxidative stress response related to most probably cytokine signalling, altered insulin related signalling and a substantial overlap between patients and muscle wasting/inflammatory animal models. MicroRNA 21 processing appeared defective suggesting that post-transcriptional protein synthesis regulation is altered by disruption of tissue microRNA expression. Finally, we were able to demonstrate that the phenotype of skeletal muscle in ICU patients is not merely one of inactivity, it appears to be an actively remodelling tissue, influenced by several mediators, all of which may be open to manipulation with the aim to improve clinical outcome. Conclusions/Significance This first combined protein and transcriptome based analysis of human skeletal muscle obtained from septic patients demonstrated that losses of mitochondria and muscle mass are accompanied by sustained protein synthesis (anabolic process) while dysregulation of transcription programmes appears to fail to compensate for increased damage and proteolysis. Our analysis identified both validated and novel clinically tractable targets to manipulate these failing processes and pursuit of these could lead to new potential treatments. Experiment Overall Design: 13 septic samples, 8 controls
2008-11-22 | E-GEOD-13205 | biostudies-arrayexpress
Project description:The growth of skeletal muscle relies on a delicate equilibrium between protein synthesis and degradation; however, how proteostasis is managed in the endoplasmic reticulum is largely unknown. Here, we report that the SEL1L-HRD1 endoplasmic reticulum (ER)-associated degradation (ERAD) complex, the primary molecular machinery that degrades misfolded proteins in the ER, is vital to maintain postnatal muscle growth and systemic energy balance. Myocyte-specific SEL1L deletion blunts the hypertrophic phase of muscle growth, resulting in a net zero gain of muscle mass during this developmental period and significant reduction in overall body growth. In addition, myocyte-specific SEL1L deletion triggered a systemic reprogramming of metabolism characterized by improved glucose sensitivity, enhanced beiging of adipocytes, and resistance to diet induced obesity. These effects were partially mediated by the upregulation of the myokine FGF21. These findings highlight the pivotal role of SEL1L-HRD1 ERAD activity in skeletal myocytes for postnatal muscle growth, and its physiological integration in maintaining whole-body energy balance.
2023-07-17 | GSE237194 | GEO
Project description:Recent studies on mouse and human skeletal muscle (SM) demonstrated the important link between mitochondrial function and the cellular metabolic adaptation. To identify key compensatory molecular mechanisms in response to chronic mitochondrial distress, we analyzed mice with ectopic SM respiratory uncoupling in uncoupling protein 1 transgenic (UCP1-TG) mice as model of muscle-specific compromised mitochondrial function. Here we describe a detailed metabolic reprogramming profile associated with mitochondrial perturbations in SM, triggering an increased protein turnover and amino acid metabolism with induced biosynthetic serine/1-carbon/glycine pathway and the longevity-promoting polyamine spermidine as well as the trans-sulfuration pathway. This is related to an induction of NADPH-generating pathways and glutathione metabolism as an adaptive mitohormetic response and defense against increased oxidative stress. Strikingly, consistent muscle retrograde signaling profiles were observed in acute stress states such as muscle cell starvation and lipid overload, muscle regeneration, and heart muscle inflammation, but not in response to exercise. We provide conclusive evidence for a key compensatory stress-signaling network that preserves cellular function, oxidative stress tolerance, and survival during conditions of increased SM mitochondrial distress, a metabolic reprogramming profile so far only demonstrated for cancer cells and heart muscle.-Ost, M., Keipert, S., van Schothorst, E. M., Donner, V., van der Stelt, I., Kipp, A. P., Petzke, K.-J., Jove, M., Pamplona, R., Portero-Otin, M., Keijer, J., and Klaus, S. Muscle mitohormesis promotes cellular survival via serine/glycine pathway flux. Control C57BL/6J wildtype male mice, aged 12 weeks, are compared to UCP1 transgene littermates fed purified low fat diet (BIOCLAIMS, Hoevenaars et al., Genes and Nutrition 2012) for 12 weeks . At the end, mice were sacrificed, gastrocnemius skeletal muscle was immediately dissected and snap frozen in liquid nitrogen. Total RNA was isolated, quantified and qualified, and subsequently used for global gene expression profiling using Agilent 8x60K microarrays. In total, 6 arrays of individual WT and 7 arrays of individual UCP1-TG samples were normalized, together with samples from the complete SUPERSERIES.
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Project description:Because myostatin normally limits skeletal muscle growth, there is an extensive effort to develop myostatin inhibitors for clinical use. One potential concern is that in patients with muscle degenerative diseases, inducing hypertrophy may increase stress on dystrophic fibers. Here, we show that blocking the myostatin pathway in dysferlin mutant mice results in early improvement in histopathology but ultimately accelerates muscle degeneration. Hence, benefits of this approach should be weighed against these potential detrimental effects. Affymetrix Mouse Exon 1.0 ST arrays were hybridized in three biologically independent experiments with RNA from quadriceps muscles of wt, Dysf-/-, F66, F66;Dysf-/- mice, and ACVR2B/Fc-injected wt and Dysf-/- mice at the age of 10 weeks (3 duplicates in 6 different groups, 18 samples).
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Project description:Ammonia is a cytotoxic molecule generated during cellular functions and by the gut microbiome. Dysregulated ammonia metabolism initiates a hyperammonemic stress response (HASR). Hyperammonemia occurs in many chronic diseases but there is limited understanding of the overall consequences of HASR. A comprehensive array of unbiased approaches was used to identify global responses during hyperammonemia with experimental validation of critical findings. Protein/gene expression and chromatin accessibility in hyperammonemic murine myotubes and mouse skeletal muscle tissue were analyzed by quantitative proteomics, RNA sequencing (RNAseq), and Assay for Transposase Accessible Chromatin Sequencing (ATACseq). Unique clusters of expression/accessibility changes were identified in hyperammonemic myotubes. In hyperammonemic mouse muscle and myotubes, we identified enrichment of pathways involved in oxidative phosphorylation, calcium signaling, hypoxia inducible factor-1, and apoptosis and regulation of protein synthesis were altered during HASR and were experimentally validated. Enrichment of senescence signaling and glycosylation pathways during HASR were novel observations. Comparisons with RNAseq data from skeletal muscle from human patients with cirrhosis revealed similar perturbations, demonstrating the translational relevance of our observations. We identified several novel regulatory pathways during HASR that are conserved in different models and across species, and whose dysregulation could significantly impact skeletal muscle structure and function.
2021-07-27 | PXD025321 | Pride
Project description:To study the combined effect of myostatin/activin inhibition and exercise on muscle mass and pathophysiology, young mdx mice, a model for Duchenne Muscular Dystrophy, were injected with soluble activin receptor-Fc (sActRIIB-Fc) or placebo (PBS) 1x/week for a 7-week period, in combination with or without voluntary running. C57Bl/10ScSnJ mice injected with PBS acted as wildtype controls. Microarray expression analysis from skeletal muscle was performed using m. gastrocnemies as the sample. We found thatexercise or a combination of exercise and sActRIIB-Fc treatment is more effective in correcting gene expression profiles of dystrophic muscles than the sActRIIB-Fc treatment alone. We also identified several pathways and proteins that were affected by exercise and sActRIIB-Fc together or independently. Total RNA obtained from gastrocnemius muscle of mdx mice divided into four groups: 1) control (injected with PBS, n=5), 2) runners (voluntary wheel running for 7 weeks, injected with PBS, n=5), 3) sActRIIB-Fc -treated (n=5), and 4) runners with sActRIIB-Fc-treatment (n=5). sActRIIB-Fc or PBS was injected intraperitoneally once a week with a 5-mg/kg dose of sActRIIB-Fc. In addition, wildtype mice served as healthy controls (n=4).
2014-10-13 | E-GEOD-52766 | biostudies-arrayexpress
Project description:Many proteins undergo glycosylation in the endoplasmic reticulum (ER) and the Golgi apparatus. Altered glycosylation can manifest in serious, sometimes fatal malfunctions. We recently showed that mutations in the cytoplasmic protein GDP-mannose pyrophosphorylase A (GMPPA) cause a syndrome characterized by alacrima, achalasia, mental retardation and myopathic alterations. GMPPA acts as feedback inhibitor of GDP-mannose pyrophosphorylase B (GMPPB), which provides GDP-mannose as a substrate for protein glycosylation. Loss of GMPPA enhances incorporation of mannose into glycochains of various proteins, including α-dystroglycan (α-DG), a protein that links the extracellular matrix with the cytoskeleton. Here, we show that loss of GMPPA affects the functionality of the Golgi apparatus using different approaches. First, we show a fragmentation of the Golgi apparatus in skeletal muscle fibers and in neurons of GMPPA KO mice. A major reorganization is also evident by mass spectrometry of KO tissues with a regulation of several ER- and Golgi-resident proteins. We further show that loss of GMPPA increases the retention of α-DG in the ER. Notably, mannose supplementation can mimic changes in ER and Golgi structure and function in WT cells. In summary, our data underline the importance of a balanced mannose homeostasis for structure and function of the secretory pathway.
2023-03-11 | PXD037129 | Pride