Circadian mRNA expression in skeletal muscle of young and aged mice
Ontology highlight
ABSTRACT: Aging animals undergo a variety of changes in molecular processes. Among these, the cellular circadian clock has been shown to change as animals age. Moreover, there is evidence that also core circadian clock proteins could influence the ageing behavior of vertebrates. To investigate the interplay between aging and the circadian clock, we studied circadian mRNA expression in skeletal muscles from young (8 weeks) and aged (80 weeks) mice. In order to detect differences in circadian patterns, we used microarray-based transcriptome-wide time series of mRNA expression, containing 16 independent measurements for both young and aged animals. Each individual time point consists of total RNA from hind limb skeletal muscles from 3 different animals. Young and aged mice where entrained to 12 hr/12 hr light-dark conditions. From these mice, hind limb skeletal muscles were extracted at different times of day, in order to measure circadian mRNA expression patterns.
Project description:Aging animals undergo a variety of changes in molecular processes. Among these, the cellular circadian clock has been shown to change as animals age. Moreover, there is evidence that also core circadian clock proteins could influence the ageing behavior of vertebrates. To investigate the interplay between aging and the circadian clock, we studied circadian mRNA expression in skeletal muscles from young (8 weeks) and aged (80 weeks) mice. In order to detect differences in circadian patterns, we used microarray-based transcriptome-wide time series of mRNA expression, containing 16 independent measurements for both young and aged animals. Each individual time point consists of total RNA from hind limb skeletal muscles from 3 different animals.
Project description:To investigate the role of the circadian clock gene Bmal1 in skeletal muscle, we compared the circadian transcriptomes of fast tibialis anterior (TA) and slow soleus (SOL) skeletal muscles from muscle-specific Bmal1 KO (mKO) and their control Cre- littermates (Ctrl). Keyword: Circadian Transcriptome, time course 72 samples were analyzed, comprised of 4 experimental groups (Ctrl SOL, mKO SOL, Ctrl TA, mKO TA), with 3 biological replicates for each time point sampled every 4 hours for 24 hours. SOL and TA muscles were collected from the same animals, as indicated by Source Animal ID data column
Project description:Peripheral arterial disease (PAD), caused by atherosclerosis, leads to limb ischemia, muscle damage, and impaired mobility in the lower extremities. Recent studies suggest that circadian rhythm disruptions can hinder vascular repair during ischemia, but the specific tissues involved and the impact on muscle health remain unclear. This study investigates the role of the skeletal muscle circadian clock in muscle adaptation to ischemic stress using a surgical mouse model of hindlimb ischemia. We used mice with specific genetic loss of the circadian clock activator, BMAL1, in adult skeletal muscle tissues (Bmal1muscle). Bmal1muscle mice and controls underwent femoral artery ligation surgery to induce hindlimb ischemia. Laser doppler imaging was used to assess limb perfusion at various time points after the surgery. Muscle tissues were analyzed with RNA sequencing and histological examination to investigate PAD-related muscle pathologies. Additionally, we studied the role of BMAL1 in muscle fiber adaptation to hypoxia using RNA and ATAC sequencing analyses in primary myotube culture model. Disrupted expression of circadian rhythm-related genes was observed in existing RNA-seq datasets from PAD patient-derived endothelial cells and ischemic limb skeletal muscles. Genetic loss of Bmal1 specifically in adult mouse skeletal muscle tissues delayed reperfusion recovery following induction of hindlimb ischemia. Histological examination of muscle tissues showed reduced regenerated myofiber number and a decreased proportion of type IIB fast-twitch myofibers in Bmal1musc mouse muscles in the ischemic limbs, but not in their contralateral non-ischemic limbs. Transcriptomic analysis revealed abrogated metabolic, angiogenic, and myogenic pathways relevant to hypoxia-adaptation in Bmal1musc mouse muscles. These changes were corroborated in Bmal1-deficient cultured primary myotubes cultured under hypoxic conditions.
Project description:Peripheral arterial disease (PAD), caused by atherosclerosis, leads to limb ischemia, muscle damage, and impaired mobility in the lower extremities. Recent studies suggest that circadian rhythm disruptions can hinder vascular repair during ischemia, but the specific tissues involved and the impact on muscle health remain unclear. This study investigates the role of the skeletal muscle circadian clock in muscle adaptation to ischemic stress using a surgical mouse model of hindlimb ischemia. We used mice with specific genetic loss of the circadian clock activator, BMAL1, in adult skeletal muscle tissues (Bmal1muscle). Bmal1muscle mice and controls underwent femoral artery ligation surgery to induce hindlimb ischemia. Laser doppler imaging was used to assess limb perfusion at various time points after the surgery. Muscle tissues were analyzed with RNA sequencing and histological examination to investigate PAD-related muscle pathologies. Additionally, we studied the role of BMAL1 in muscle fiber adaptation to hypoxia using RNA and ATAC sequencing analyses in primary myotube culture model. Disrupted expression of circadian rhythm-related genes was observed in existing RNA-seq datasets from PAD patient-derived endothelial cells and ischemic limb skeletal muscles. Genetic loss of Bmal1 specifically in adult mouse skeletal muscle tissues delayed reperfusion recovery following induction of hindlimb ischemia. Histological examination of muscle tissues showed reduced regenerated myofiber number and a decreased proportion of type IIB fast-twitch myofibers in Bmal1musc mouse muscles in the ischemic limbs, but not in their contralateral non-ischemic limbs. Transcriptomic analysis revealed abrogated metabolic, angiogenic, and myogenic pathways relevant to hypoxia-adaptation in Bmal1musc mouse muscles. These changes were corroborated in Bmal1-deficient cultured primary myotubes cultured under hypoxic conditions.
Project description:Peripheral arterial disease (PAD), caused by atherosclerosis, leads to limb ischemia, muscle damage, and impaired mobility in the lower extremities. Recent studies suggest that circadian rhythm disruptions can hinder vascular repair during ischemia, but the specific tissues involved and the impact on muscle health remain unclear. This study investigates the role of the skeletal muscle circadian clock in muscle adaptation to ischemic stress using a surgical mouse model of hindlimb ischemia. We used mice with specific genetic loss of the circadian clock activator, BMAL1, in adult skeletal muscle tissues (Bmal1muscle). Bmal1muscle mice and controls underwent femoral artery ligation surgery to induce hindlimb ischemia. Laser doppler imaging was used to assess limb perfusion at various time points after the surgery. Muscle tissues were analyzed with RNA sequencing and histological examination to investigate PAD-related muscle pathologies. Additionally, we studied the role of BMAL1 in muscle fiber adaptation to hypoxia using RNA and ATAC sequencing analyses in primary myotube culture model. Disrupted expression of circadian rhythm-related genes was observed in existing RNA-seq datasets from PAD patient-derived endothelial cells and ischemic limb skeletal muscles. Genetic loss of Bmal1 specifically in adult mouse skeletal muscle tissues delayed reperfusion recovery following induction of hindlimb ischemia. Histological examination of muscle tissues showed reduced regenerated myofiber number and a decreased proportion of type IIB fast-twitch myofibers in Bmal1musc mouse muscles in the ischemic limbs, but not in their contralateral non-ischemic limbs. Transcriptomic analysis revealed abrogated metabolic, angiogenic, and myogenic pathways relevant to hypoxia-adaptation in Bmal1musc mouse muscles. These changes were corroborated in Bmal1-deficient cultured primary myotubes cultured under hypoxic conditions.
Project description:To investigate the role of the circadian clock gene Bmal1 in skeletal muscle, we compared the circadian transcriptomes of fast tibialis anterior (TA) and slow soleus (SOL) skeletal muscles from muscle-specific Bmal1 KO (mKO) and their control Cre- littermates (Ctrl). Keyword: Circadian Transcriptome, time course
Project description:During aging, the number and functionality of muscle stem cells (MuSCs) decreases leading to impaired regeneration of aged skeletal muscle. In addition to intrinsic changes in aged MuSCs, extracellular matrix (ECM) proteins deriving from other cell types, e.g., fibrogenic-adipogenic progenitor cells (FAPs), contribute to the aging phenotype of MuSCs and impaired regeneration in the elderly. So far, no comprehensive analysis on how age-dependent changes in the whole skeletal muscle proteome affect MuSC function have been conducted. Here, we investigated age-dependent changes in the proteome of different skeletal muscle types by applying deep quantitative mass spectrometry. We identified 183 extracellular matrix proteins that show different abundances in skeletal muscles of old mice. By integrating single cell sequencing data, we reveal that transcripts of those ECM proteins are mainly expressed in FAPs, suggesting that FAPs are the main contributors to ECM remodelling during aging. We functionally investigated one of those ECM molecules, namely Smoc2, which is aberrantly expressed during aging. We show that Smoc2 levels are elevated during regeneration and that its accumulation in the aged MuSC niche causes impairment of MuSCs function through constant activation of integrin/MAPK signaling. In vivo, supplementation of exogenous Smoc2 hampers the regeneration of young muscles following serial injuries, leading to a phenotype reminiscent of regenerating aged skeletal muscle. Taken together, we provide a comprehensive resource of changes in the composition of the ECM of aged skeletal muscles, we pinpoint the cell types driving these changes, and we identify a new niche protein causing functional impairment of MuSCs thereby hampering the regeneration capacity of skeletal muscles.
Project description:During aging, the number and functionality of muscle stem cells (MuSCs) decreases leading to impaired regeneration of aged skeletal muscle. In addition to intrinsic changes in aged MuSCs, extracellular matrix (ECM) proteins deriving from other cell types, e.g., fibrogenic-adipogenic progenitor cells (FAPs), contribute to the aging phenotype of MuSCs and impaired regeneration in the elderly. So far, no comprehensive analysis on how age-dependent changes in the whole skeletal muscle proteome affect MuSC function have been conducted. Here, we investigated age-dependent changes in the proteome of different skeletal muscle types by applying deep quantitative mass spectrometry. We identified 183 extracellular matrix proteins that show different abundances in skeletal muscles of old mice. By integrating single cell sequencing data, we reveal that transcripts of those ECM proteins are mainly expressed in FAPs, suggesting that FAPs are the main contributors to ECM remodelling during aging. We functionally investigated one of those ECM molecules, namely Smoc2, which is aberrantly expressed during aging. We show that Smoc2 levels are elevated during regeneration and that its accumulation in the aged MuSC niche causes impairment of MuSCs function through constant activation of integrin/MAPK signaling. In vivo, supplementation of exogenous Smoc2 hampers the regeneration of young muscles following serial injuries, leading to a phenotype reminiscent of regenerating aged skeletal muscle. Taken together, we provide a comprehensive resource of changes in the composition of the ECM of aged skeletal muscles, we pinpoint the cell types driving these changes, and we identify a new niche protein causing functional impairment of MuSCs thereby hampering the regeneration capacity of skeletal muscles.
Project description:To identify atrophy genes directly targeted by Bcl-3 transactivator at a genome wide level, we performed whole transcript expression array and ChIP-seq for muscles from weight bearing or 5-day hind limb unloaded mice. Genes that showed increased expression with unloading and a Bcl-3 peak in the promoter (from ChIP-seq data) were considered as Bcl-3 direct targets during disuse atrophy. Using ChIP array, we identified 241 direct targets for Bcl-3. Our data describe Bcl-3 as a global regulator both of the proteolysis and the change in energy metabolism that are essential components of muscle atrophy due to disuse. Disuse skeletal muscle atrophy was induced by hind limb unloading. Weight bearing (WB) or 5-day hind limb unloaded (HU) muscles were harvested for total RNA isolation and processed for whole transcript expression profiling. We chose to examine gene expression and Bcl-3 binding from 5-day unloaded muscles because our previous time course study of disuse atrophy suggested that most genes are differentially regulated at this time point, and thus, would best represent the time for Bcl-3 binding to the gene targets of the NF-kB transcriptional network.
Project description:Rodent hind limb unloading was used as a model for reduced muscle activity and eventual atrophy. After a 10 day period of unloading, mice in this study were “reloaded” for 3 days and regained use of their hind limbs. We report the application of Next-generation sequencing (NGS) technology for high-throughput profiling of mRNA in soleus muscle of adult (6 mo) and aged (22-24 mo) mice. Our goal was to determine the effects of hind limb unloading and reloading on mRNA profiles in soleus muscle and compare between adult and aged mice. We find that there are distinct response in the profile of fatty acid oxidation, TCA cycle, ETC oxidative phosphorylation gene expression patterns in response to unloading and reloading. The repsonses are generally simialr between young and old mice.