Project description:Microarray analysis was performed with RNA isolated from vastus lateralis muscle biopsies of lean/overweight subjects following 18 days of aerobic exercise training. Samples from lean active individuals were also included. Exercise training led to robust changes in trained muscle. The lean active group profile was distinct from the pre-exercise samples. These results help define the molecular changes associated with aerobic training and contrast with an active phenotype.
Project description:Skeletal muscle has a unique ability to remodel in response to stimuli such as contraction and aerobic exercise training. Phenotypic changes in muscle that occur with training such as a switch to a more oxidative fiber type, and increased capillary density contribute to the well-known health benefits of aerobic exercise. The muscle matrisome likely plays an important role in muscle remodeling with exercise. However, due to technical limitations in studying muscle ECM proteins, which are highly insoluble, little is known about the muscle matrisome and how it contributes to muscle remodeling. Here, we utilized two-fraction methodology to extract muscle proteins, combined with multiplexed tandem mass tag proteomic technology to identify 161 unique ECM proteins in mouse skeletal muscle. In addition, we demonstrate that aerobic exercise training induces remodeling of a significant proportion of the muscle matrisome. We performed follow-up experiments to validate exercise-regulated ECM targets in a separate cohort of mice using Western blotting and immunofluorescence imaging. Our data demonstrate that changes in several key ECM targets are strongly associated with muscle remodeling processes such as increased capillary density in mice. We also identify LOXL1 as a novel muscle ECM target associated with aerobic capacity in humans. In addition, publically available data and databases were used for in silico modeling to determine the likely cellular sources of exercise-induced ECM remodeling targets and identify ECM interaction networks. This work greatly enhances our understanding of ECM content and function in skeletal muscle and demonstrates an important role for ECM remodeling in the adaptive response to exercise.
Project description:Low aerobic exercise capacity is a risk factor for diabetes and strong predictor of mortality; yet some individuals are exercise resistant, and unable to improve exercise capacity through exercise training. To test the hypothesis that resistance to aerobic exercise training underlies metabolic disease-risk, we used selective breeding for 15 generation to develop rat models of low- and high-aerobic response to training. Before exercise training, rats selected as low- and high-responders had similar exercise capacities. However, after 8-wks of treadmill training low-responders failed to improve their exercise capacity, while high-responders improved by 54%. Remarkably, low-responders to aerobic training exhibited pronounced metabolic dysfunction characterized by insulin resistance and increased adiposity, demonstrating that the exercise resistant phenotype segregates with disease risk. Low-responders had impaired exercise-induced angiogenes0is in muscle; however, mitochondrial capacity was intact and increased normally with exercise training, demonstrating that mitochondria are not limiting for aerobic adaptation or responsible for metabolic dysfunction in low-responders. Low-responders had increased stress/inflammatory signaling and altered TGFM-NM-2 signaling, characterized by hyperphosphorylation of a novel exercise-regulated phosphorylation site on SMAD2. Using this powerful biological model system we have discovered key pathways for low exercise training response that may represent novel targets for the treatment of metabolic disease. Cardiac and skeletal muscle from 3 high and 3 low responder rats were examined for differential miRNA expression using Exiqon microarrays
Project description:In our study, we investigated for contractile activity-specific changes in the transcriptome in untrained and trained (after an aerobic training programme) human skeletal muscle. The second goal was to examine effect of aerobic training on gene expression in muscle at baseline (after long term training). Seven untrained males performed the one-legged knee extension exercise (for 60 min) with the same relative intensity before and after a 2 month aerobic training programme (1 h/day, 5/week). Biopsy samples were taken at rest (baseline condition, 48 h after exercise), 1 and 4 h after the one-legged exercise from m. vastus lateralis of either leg. Comparison of gene expression in exercised leg with that in non-exercised [control] leg allowed us to identify contractile activity-specific genes in both untrained and trained skeletal muscle, i.e., genes that play a key role in adapting to acute exercise, regardless of the level of fitness. RNA-sequencing (84 samples in total; ~47 million reads/sample) was performed by NextSeq 500 and HiSeq 2500 (Illumina). Two months aerobic training increased the aerobic capacity of the knee-extensor muscles (power at anaerobic threshold in the incremental one-legged and cycling tests), the maximum rate of ADP-stimulated mitochondrial respiration in permeabilized muscle fibres and amounts of oxidative phosphorylation proteins. Contractile activity-specific changes in the transcriptome in untrained and trained human skeletal muscle were revealed for the first time. After 2 month aerobic training, transcriptome responses specific for contractile activity in trained muscle substantially decreased relative to those in untrained muscle. We found out that adaptation of skeletal muscle to regular exercise is associated not only with a transient change in the transcriptome after each stress (acute exercise), but also with a marked change in baseline expression of many genes after repeated stress (e.g., long term training).
Project description:The molecular pathways which are activated and contribute to physiological remodeling of skeletal muscle in response to endurance exercise have not been fully characterized. We previously reported that ~800 gene transcripts are regulated following 6 weeks of supervised endurance training in young sedentary males, referred to as the training responsive transcriptome (TRT). Here we utilized this database together with data on biological variation in muscle adaptation to aerobic endurance training in both humans and a novel out-bred rodent model to study the potential regulatory molecules that coordinate this complex network of genes. We identified three DNA sequences representing RUNX1, SOX9, and PAX3 transcription factor binding sites as over-represented in the TRT. In turn, miRNA profiling indicated that several miRNAs targeting RUNX1, SOX9 and PAX3 were down-regulated by endurance training. The TRT was then examined by contrasting subjects who demonstrated the least vs. the greatest improvement in aerobic capacity (low vs. high responders), and at least 100 of the 800 TRT genes were differentially regulated, thus suggesting regulation of these genes may be important for improving aerobic capacity. In high responders, pro-angiogenic and tissue developmental networks emerged as key candidates for coordinating tissue aerobic adaptation. Beyond RNA level validation there were several DNA variants that associated with VO(2)max trainability in the HERITAGE Family Study but these did not pass conservative Bonferroni adjustment. In addition, in a rat model selected across 10 generations for high aerobic training responsiveness, we found that both the TRT and a homologous subset of the human high responder genes were regulated to a greater degree in high responder rodent skeletal muscle. This analysis provides a comprehensive map of the transcriptomic features important for aerobic exercise-induced improvements in maximal oxygen consumption. This data is from skeletal muscle post 6 weeks of endurance exercise training.
Project description:In the present study 23 participants completed three months of supervised aerobic exercise training of one leg (training period 1) followed by 9 months of rest before 12 of the participants completed a second exercise training period (training period 2) of three months of both legs. Skeletal muscle biopsies have been collected before and after the training periods. We have compared trained leg with untrained leg and studied gene and isoform expression. Additional samples included in this study has been previously submitted (GEO accession number GSE58387 and GSE60590). Analyze of transcriptome in skeletal muscle biopsy samples in response to exercise training in 23 participants in total (in addition to data previously submitted GEO accession number GSE58387 and GSE60590). Biopsy is collected from skeletal muscle before and after training period.
Project description:This study aimed to determine skeletal muscle DNA methylation changes in a cohort of volunteers with a range of insulin sensitivities following 8-weeks of supervised exercise training. We studied 13 sedentary participants (5M/8F, 34.6 ± 3.1 years) and performed euglycemic hyperinsulinemic clamps with vastus lateralis muscle biopsies and peak aerobic activity (VO2 peak) tests before and after training. We extracted DNA from the muscle biopsies and performed global methylation using Illumina's Methylation EPIC 850K BeadChip.
Project description:A total of 23 participants (data available in present submission and in GSE58608) completed three months of supervised aerobic exercise training of one leg. Skeletal muscle biopsies have been collected before and after the training period. We have investigated differences between trained and untrained leg and before and after training by studying the gene and isoform expression. Additional samples present in this study has been previously published (GEO accession number GSE58608). Analysis of transcriptome in skeletal muscle biopsy samples in response to exercise training in 22 participants (of the total 23 participants). One biopsy is collected from each leg before and after training period.
Project description:Low aerobic exercise capacity is a risk factor for diabetes and strong predictor of mortality; yet some individuals are exercise resistant, and unable to improve exercise capacity through exercise training. To test the hypothesis that resistance to aerobic exercise training underlies metabolic disease-risk, we used selective breeding for 15 generation to develop rat models of low- and high-aerobic response to training. Before exercise training, rats selected as low- and high-responders had similar exercise capacities. However, after 8-wks of treadmill training low-responders failed to improve their exercise capacity, while high-responders improved by 54%. Remarkably, low-responders to aerobic training exhibited pronounced metabolic dysfunction characterized by insulin resistance and increased adiposity, demonstrating that the exercise resistant phenotype segregates with disease risk. Low-responders had impaired exercise-induced angiogenes0is in muscle; however, mitochondrial capacity was intact and increased normally with exercise training, demonstrating that mitochondria are not limiting for aerobic adaptation or responsible for metabolic dysfunction in low-responders. Low-responders had increased stress/inflammatory signaling and altered TGFβ signaling, characterized by hyperphosphorylation of a novel exercise-regulated phosphorylation site on SMAD2. Using this powerful biological model system we have discovered key pathways for low exercise training response that may represent novel targets for the treatment of metabolic disease.
Project description:In the present study 23 participants completed three months of supervised aerobic exercise training of one leg (training period 1) followed by 9 months of rest before 12 of the participants completed a second exercise training period (training period 2) of three months of both legs. Skeletal muscle biopsies have been collected before and after the training periods. We have compared trained leg with untrained leg and studied gene and isoform expression. Additional samples included in this study has been previously submitted (GEO accession number GSE58387 and GSE60590).