Down-regulation of JunB by RNAi in mouse muscles in vivo
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE18664 | GEO | 2010/01/01
SECONDARY ACCESSION(S): PRJNA121529
REPOSITORIES: GEO
Similar Datasets
Project description:The myogenic regulatory factor MRF4 is expressed at high levels in myofibers of adult skeletal muscle, but its function is unknown. Here we show that knockdown of MRF4 in adult muscle causes hypertrophy and prevents denervation-induced atrophy. This effect is accompanied by increased protein synthesis and the widespread activation of genes involved in muscle contraction, excitation-contraction coupling and energy metabolism, many of which are known targets of MEF2 transcription factors. Genes regulated by MEF2 represent the top-ranking gene set enriched after Mrf4 RNAi, and a MEF2 reporter is inhibited by co-transfected MRF4 and activated by Mrf4 RNAi. The role of MEF2 in mediating the effect of MRF4 knockdown is supported by the finding that Mrf4 RNAi-dependent increase in fiber size is prevented by dominant negative MEF2, while constitutively active MEF2 is able to induce myofiber hypertrophy. The nuclear localization of the MEF2 co-repressor HDAC4 is impaired by Mrf4 knockdown, suggesting that MRF4 acts by stabilizing a repressor complex that controls MEF2 activity. The demonstration that fiber size in adult skeletal muscle is controlled by the MRF4-MEF2 axis opens new perspectives in the search for therapeutic targets to prevent muscle wasting, in particular sarcopenia and cachexia. Adult innervated and denervated rat soleus muscles were transfected with shRNA to Mrf4 (M1) or to LacZ as a control. Muscles were dissected and examined after 7 days. For each group/condition we selected three different muscles (biological replicas).
2016-07-15 | E-GEOD-67069 | biostudies-arrayexpress
Project description:For additional details see Bongers et al, Spermine Oxidase Maintains Basal Skeletal Muscle Gene Expression and Fiber Size, and Is Strongly Repressed by Conditions that Cause Skeletal Muscle Atrophy . Am J Physiol Endocrinol Metab. 2014 [under review] Bilateral tibialis anterior muscles of C57BL/6 mice were harvested seven days after transfection with p21 or control plasmid.
2014-12-04 | E-GEOD-63007 | biostudies-arrayexpress
Project description:For additional details see Bongers et al, Spermine Oxidase Maintains Basal Skeletal Muscle Gene Expression and Fiber Size, and Is Strongly Repressed by Conditions that Cause Skeletal Muscle Atrophy . Am J Physiol Endocrinol Metab. 2014 [under review] Bilateral tibialis anterior muscles of C57BL/6 mice were harvested seven days after transfection with spermine oxidase or control plasmid.
2014-12-04 | E-GEOD-63006 | biostudies-arrayexpress
Project description:Under stress conditions mammalian cells activate compensatory mechanisms to survive and maintain cellular function. During catabolic conditions, such as low nutrients, systemic inflammation, cancer or infections, protein breakdown is enhanced and aminoacids are released from muscles to sustain liver gluconeogenesis and tissues protein synthesis. Proteolysis in muscle is orchestrated by a set of genes named atrophy-related genes. A system that is activated both in short and prolonged stress conditions is the family of Forkhead Box (Fox) O transcription factors. Here, we report that muscle-specific deletion of FoxO members resulted in protection from muscle loss because FoxO family is required for induction of autophagy-lysosome and ubiquitin-proteasome systems. Importantly, FoxOs are required for Akt activity but not for mTOR signalling underlining the concept that FoxOs are upstream mTOR for the control of protein breakdown when nutrients are lacking. Moreover, FoxO family controls the induction of critical genes belonging to several fundamental stress response pathways such as unfolded protein response, ROS detoxification and translational regulation. Finally, we identify a set of novel FoxO-dependent ubiquitin ligases including the recent discovered MUSA11 and a new one, which we named Specific of Muscle Atrophy and Regulated by Transcription (SMART). Our findings identify the critical role of FoxO in regulating a variety of genes belonging to pathways important for stress-response under catabolic conditions. Gene expression in muscles of muscle-specific FoxO 1,3,4 knock-out mice that were fed normally or starved
2015-04-24 | GSE52667 | GEO
Project description:Consumption of a protein containing meal by a fasted animal promotes protein accretion in skeletal muscle, in part through leucine stimulation of protein synthesis and indirectly through repression of protein degradation mediated by its metabolite, α-ketoisocaproate. Mice lacking the mitochondrial branched-chain aminotransferase (BCATm/Bcat2), that interconverts leucine and α-ketoisocaproate, exhibit elevated protein turnover. Here, the transcriptomes of gastrocnemius muscle from BCATm knockout (KO) and wildtype mice were compared using Next Generation RNA-Sequencing (RNA-Seq) to identify potential adaptations associated with their persistently altered nutrient signaling. Statistically significant changes in the abundance of 1486/~39,010 genes were identified. Bioinformatics analysis of the RNA-Seq data indicated that pathways involved in protein synthesis (eIF2, mTOR, eIF4 and p70S6K pathways including 40S and 60S ribosomal proteins), protein breakdown (e.g., ubiquitin mediated), and muscle degeneration (apoptosis, atrophy, myopathy and cell death) were up-regulated. Also in agreement with our previous observations, the abundance of mRNAs associated with reduced body size, glycemia, plasma insulin, and lipid signaling pathways were observed in BCATm KO mice. Consistently, genes encoding anaerobic and/or oxidative metabolism of carbohydrate, fatty acids and BCAAs were modestly but systematically reduced. Although there was no indication that muscle fiber type was different between KO and wildtype mice, a difference in the abundance of mRNAs associated with a muscular dystrophy phenotype was observed, consistent with the published exercise intolerance of these mice. The results suggest transcriptional adaptations occur in BCATm KO mice that along with altered nutrient signaling may contribute to their previously reported protein turnover, metabolic and exercise phenotypes. Comparison of wildtype and BCATm KO gastrocnemius biological replicates
2015-12-11 | E-GEOD-68915 | biostudies-arrayexpress
Project description:To identify novel atrophy-related genes, which are controlled by BMP signaling, we performed gene expression profiling on innervated and 14 days denervated muscles of Smad4 knockout and control mice, focusing on genes that were differentially upregulated in denervated Smad4-/- muscles compared to controls. Among the different genes our attention was attracted by a gene that encodes for a novel f-box protein (Fbxo30) belonging to the SCF complex family of the ubiquitin ligases. Cell size is determined by the balance between protein synthesis and degradation. This equilibrium is affected by hormones, nutrients, energy levels, mechanical stress and cytokines. Mutations that inactivate Myostatin lead to important muscle growth in animals and humans. However, the signals and pathways responsible for this hypertrophy remain largely unknown. Here we find that BMP signaling, acting through Smad1/5/8, is the fundamental hypertrophic signal. Inhibition of BMP signaling causes muscle atrophy, abolishes the hypertrophic phenotype of Myostatin knockout and strongly exacerbates the effects of denervation and fasting. BMP-Smad1/5/8 negatively regulates a novel gene (Fbxo30) that encodes an ubiquitin ligase, that is required for muscle loss. Collectively, these data identify a critical role for the BMP pathway in adult muscle maintenance, growth and atrophy. Gene expression profiling on innervated and 14 days denervated muscles of Smad4 knockout and control mice. Three independent experiments were performed for each experimental condition using different animals for each experiment.
2013-09-17 | E-GEOD-49826 | biostudies-arrayexpress
Project description:Under stress conditions mammalian cells activate compensatory mechanisms to survive and maintain cellular function. During catabolic conditions, such as low nutrients, systemic inflammation, cancer or infections, protein breakdown is enhanced and aminoacids are released from muscles to sustain liver gluconeogenesis and tissues protein synthesis. Proteolysis in muscle is orchestrated by a set of genes named atrophy-related genes. A system that is activated both in short and prolonged stress conditions is the family of Forkhead Box (Fox) O transcription factors. Here, we report that muscle-specific deletion of FoxO members resulted in protection from muscle loss because FoxO family is required for induction of autophagy-lysosome and ubiquitin-proteasome systems. Importantly, FoxOs are required for Akt activity but not for mTOR signalling underlining the concept that FoxOs are upstream mTOR for the control of protein breakdown when nutrients are lacking. Moreover, FoxO family controls the induction of critical genes belonging to several fundamental stress response pathways such as unfolded protein response, ROS detoxification and translational regulation. Finally, we identify a set of novel FoxO-dependent ubiquitin ligases including the recent discovered MUSA11 and a new one, which we named Specific of Muscle Atrophy and Regulated by Transcription (SMART). Our findings identify the critical role of FoxO in regulating a variety of genes belonging to pathways important for stress-response under catabolic conditions. Gene expression in muscles of muscle-specific FoxO 1,3,4 knock-out mice that were fed normally or starved We generated knocked-out FoxO 1,3,4 specifically in muscle by crossing FoxO1-3-4-floxed mice (FoxO1,3,4 f/f) with a transgenic line expressing Cre recombinase under the control of MLC1f promoter to generate muscle-specific FoxO1,3,4 triple knockout mice. These mice were either fed ad libitum or starved. Subsequently gene expression of the gastrocnemius muscles was analyzed. For each of the 4 conditions (FOXO1,3,4 f/f fed or starved, FOXO1,3,4-/- fed or starved), we isolated the gastrocnemius muscles of 3 mice thus yielding 6 muscles per condition. RNA was prepared from these muscles using the TRIzol method (Life Technologies) followed by cleanup with the RNeasy kit (QIAGEN). RNA concentration was determined by spectrophotometry and quality of the RNA was monitored using the Agilent 2100 Bioanalyzer (Agilent Technologies). RNA of the 6 muscles per condition was pooled equimolarly and used for further microarray analysis. cRNA was prepared, labelled and hybridised to Affymetrix Mouse Genome 430 2.0 Arrays using Affymetrix-supplied kits and according to standard Affymetrix protocols. Expression values were summarized using the Mas 5.0 algorithm. Genes that were up- or downregulated upon starvation compared to the fed condition were determined using Excel software. A threshold of 1.5 was used for the fold up-or downregulation consistent with the fold change that can be reliably detected with these type of arrays.
2015-04-24 | E-GEOD-52667 | biostudies-arrayexpress
Project description:Muscle size is controlled by the PI3K-PKB/Akt-mTORC1-FoxO pathway, which integrates signals from growth factors, energy and amino acids to activate protein synthesis and inhibit protein breakdown. While mTORC1 activity is necessary for PKB/Akt-induced muscle hypertrophy, its constant activation alone induces muscle atrophy. Here we show that this paradox is based on mTORC1 activity promoting protein breakdown through the ubiquitin-proteasome system (UPS) by simultaneously inducing ubiquitin E3 ligase expression via feedback inhibition of PKB/Akt and proteasome biogenesis via Nuclear Factor Erythroid 2-Like 1 (Nrf1). Muscle growth was restored by reactivation of PKB/Akt, but not by Nrf1 knockdown, implicating ubiquitination as the limiting step. However, both PKB/Akt activation and proteasome depletion by Nrf1 knockdown led to an immediate disruption of proteome integrity with rapid accumulation of damaged material. These data highlight the physiological importance of mTORC1-mediated PKB/Akt inhibition and point to juxtaposed roles of the UPS in atrophy and proteome integrity.
2022-10-28 | PXD034117 | Pride
Project description:Skeletal muscle atrophy is a serious and highly prevalent condition that remains poorly understood at the molecular level. Previous work found that skeletal muscle atrophy involves an increase in skeletal muscle Gadd45a expression, which is necessary and sufficient for skeletal muscle fiber atrophy. However, the direct mechanism by which Gadd45a promotes skeletal muscle atrophy was unknown. To address this question, we biochemically isolated skeletal muscle fiber proteins that associate with Gadd45a as it induces skeletal muscle atrophy in living mice. We found that Gadd45a interacts with multiple proteins in skeletal muscle fibers, including, most prominently, the MAP kinase kinase kinase MEKK4. Furthermore, by forming a complex with MEKK4 in skeletal muscle fibers, Gadd45a increases MEKK4 protein kinase activity, which is sufficient to induce skeletal muscle fiber atrophy and required for Gadd45a-mediated skeletal muscle fiber atrophy. Together, these results identify a direct biochemical mechanism by which Gadd45a induces skeletal muscle atrophy and provide new insight into way that skeletal muscle atrophy occurs at the molecular level.
2016-05-17 | MSV000079730 | MassIVE
Project description:Skeletal muscle atrophy is a consequence of many diseases, environmental insults, inactivity, age and injury. Atrophy is characterized by active degradation and removal of contractile proteins and a reduction in fiber size. Animal models have been extensively used to identify pathways leading to atrophic conditions. Here we have used genome-wide expression profiling analysis and quantitative PCR to identify the molecular changes that occur in two clinically relevant animal mouse models of muscle atrophy, hindlimb casting and Achilles tendon laceration (tenotomy). Gastrocnemius muscle samples were collected 2, 7 and 14 days after insult. The total amount of muscle loss as measured by wet weight and muscle fiber size was equivalent between models, although tenotomy resulted in a more rapid induction of muscle atrophy. Furthermore, tentomy resulted in the regulation of significantly more mRNA transcripts then casting. Analysis of the regulated genes and pathways suggest that the mechanism of atrophy is distinct between these models. The degradation following casting appears ubiquitin-proteasome-mediated while degradation following tenotomy appears lysosomal and matrix-metalloproteinase (MMP)-mediated. This data suggests that there are multiple mechanisms leading to muscle atrophy and that specific therapeutic agents may be necessary to combat the atrophy seen under different conditions. Muscle atrophy was induced through two methods; unloading induced by tendon laceration (Tenotomy) and immobilization induced by hindlimb casting (Casting). For the tenotomy, eight week old male C57/B6 mice were anesthetized by ether inhalation and subsequent intramuscular injection of ketamine-xylazine (0.1 ml/g). The right Achilles tendon just proximal to the calcaneus was severed with a sterile scalpel. The mice were allowed to recover and move freely about their cage. An additional cohort of animals was sham operated (Sham) which involved isolation and manipulation of the Achilles tendon without laceration. For the casting, the right hindlimbs of eight week old male C57Bl/6 mice were immobilized through casting. After 2, 7 or 14 days, animals were sacrificed and the left and right gastrocnemius muscles were carefully removed, flash frozen in liquid nitrogen, and stored at -80°C for further processing. The left untreated legs served as controls. A group of naïve animals that received no treatment or manipulation was included as an additional control. Each group consisted of between 5 and 10 samples for a total of 111 individual samples.
2011-10-24 | E-GEOD-25908 | biostudies-arrayexpress