Project description:The processes of adaptation to environmental heat and aerobic exercise training improve efficiency in various body systems and bring about acclimatory homeostasis. In order to examine the global genomic responses of the soleus and heart following exposure of rats to these stressors, nylon cDNA Atlas Array was used. Male rats were exposed to one of the following stressors: heat acclimation, aerobic training (treadmill), and combined heat acclimation and aerobic training for short (2, 3 days) and long (1 mo) time period. The study comprised seven experimental groups: Controls-untreated. Heat acclimated groups (2dac, Acc)â exposure to environmental heat at 34C for 2 or 30 days. Exercise groups (3dex, Ex)â graduated training protocol under normothermic conditions for 3 and 30 days at 24C. Exercise training and heat acclimation â (3dexac, ExAc)- exposed to both environmental heat and aerobic exercise as above. The Series data tables appended below: 1) Heart - normalized log2 ratio of geomeans defined as treatment/control 2) Soleus - normalized log2 ratio of geomeans defined as treatment/control 21 samples, 3 pool each, of: 1)Â Control untreated rats 2)Â Long-term heat acclimated rats 3)Â Long-term aerobic-exercised trained rats. 4)Â Rats exposed to long-term heat acclimation and exercise training. 5)Â Short term heat acclimated rats. 6)Â Short term aerobic exercised trained rats 7)Â Rats exposed to short-term heat acclimation and exercise training.
Project description:The processes of adaptation to environmental heat and aerobic exercise training improve efficiency in various body systems and bring about acclimatory homeostasis. In order to examine the global genomic responses of the soleus and heart following exposure of rats to these stressors, nylon cDNA Atlas Array was used. Male rats were exposed to one of the following stressors: heat acclimation, aerobic training (treadmill), and combined heat acclimation and aerobic training for short (2, 3 days) and long (1 mo) time period. The study comprised seven experimental groups: Controls-untreated. Heat acclimated groups (2dac, Acc)– exposure to environmental heat at 34C for 2 or 30 days. Exercise groups (3dex, Ex)– graduated training protocol under normothermic conditions for 3 and 30 days at 24C. Exercise training and heat acclimation – (3dexac, ExAc)- exposed to both environmental heat and aerobic exercise as above. The Series data tables appended below: 1) Heart - normalized log2 ratio of geomeans defined as treatment/control 2) Soleus - normalized log2 ratio of geomeans defined as treatment/control Keywords: stress response
Project description:Purpose: Aerobic capacity is a strong predictor of cardiovascular mortality. To determine the relationship between inborn aerobic capacity and soleus gene expression we examined genome-wide gene expression in soleus muscle of rats artificially selected for high and low running capacity (HCR and LCR, respectively) over 16 generations. The artificial selection of LCR caused accumulation of risk factors of cardiovascular disease similar to the metabolic syndrome seen in man, whereas HCR had markedly better cardiac function. We also studied alterations in gene expression in response to exercise training in the two groups, since accumulating evidence indicates that exercise has profound beneficial effects on the metabolic syndrome. Methods:; Soleus gene expression of both sedentary and exercise trained HCR and LCR was characterized by microarray- and gene ontology analysis. Results: Although HCR and LCR had an inborn 347% difference in running capacity, only three genes were found differentially expressed in the soleus muscle between the two groups. Up-regulation of the mitochondrial enzyme leucyl-transferRNA synthetase (LARS2) was found in the sedentary LCR. Increased expression of LARS2 has been associated with a mitochondrial DNA mutation linked to maternally inherited diabetes and mitochondrial dysfunction. In line with our findings, a growing body of evidence suggests that LCR have compromised mitochondrial function. After exercise training, 58 genes were altered in the soleus muscle of HCR, in contrast to only one in the LCR group. This suggests that animals born with different levels of fitness respond different to the same type of exercise training. Adaptations to exercise in HCR seemed to be associated with increased lipid metabolism and fatty acid elongation in the mitochondria. Also, genes associated with the peroxisomes, seemed to be central in the adaptation to exercise. Conclusion: The results indicate that (i) LCR might have mitochondrial dysfunction, which may be a contributing factor of the low inborn aerobic capacity, (ii) animals born with different levels of fitness respond different to the same exercise program. Experiment Overall Design: There are 16 samples in this study.
Project description:Purpose: Aerobic capacity is a strong predictor of cardiovascular mortality. To determine the relationship between inborn aerobic capacity and soleus gene expression we examined genome-wide gene expression in soleus muscle of rats artificially selected for high and low running capacity (HCR and LCR, respectively) over 16 generations. The artificial selection of LCR caused accumulation of risk factors of cardiovascular disease similar to the metabolic syndrome seen in man, whereas HCR had markedly better cardiac function. We also studied alterations in gene expression in response to exercise training in the two groups, since accumulating evidence indicates that exercise has profound beneficial effects on the metabolic syndrome. Methods: Soleus gene expression of both sedentary and exercise trained HCR and LCR was characterized by microarray- and gene ontology analysis. Results: Although HCR and LCR had an inborn 347% difference in running capacity, only three genes were found differentially expressed in the soleus muscle between the two groups. Up-regulation of the mitochondrial enzyme leucyl-transferRNA synthetase (LARS2) was found in the sedentary LCR. Increased expression of LARS2 has been associated with a mitochondrial DNA mutation linked to maternally inherited diabetes and mitochondrial dysfunction. In line with our findings, a growing body of evidence suggests that LCR have compromised mitochondrial function. After exercise training, 58 genes were altered in the soleus muscle of HCR, in contrast to only one in the LCR group. This suggests that animals born with different levels of fitness respond different to the same type of exercise training. Adaptations to exercise in HCR seemed to be associated with increased lipid metabolism and fatty acid elongation in the mitochondria. Also, genes associated with the peroxisomes, seemed to be central in the adaptation to exercise. Conclusion: The results indicate that (i) LCR might have mitochondrial dysfunction, which may be a contributing factor of the low inborn aerobic capacity, (ii) animals born with different levels of fitness respond different to the same exercise program. Keywords: aerobic capacity, metabolic syndrome, soleus muscle, gene expression, metabolism
Project description:Background: Cold acclimation and exercise training were previously shown to increase peripheral insulin sensitivity in human volunteers with type 2 diabetes. Although cold is a potent activator of brown adipose tissue, the increase in peripheral insulin sensitivity by cold is largely mediated by events occurring in skeletal muscle and at least partly involves GLUT4 translocation, as is also observed for exercise training. Results: To investigate if cold acclimation and exercise training overlap in the molecular adaptive response in skeletal muscle, we performed transcriptomics analysis on vastus lateralis muscle collected from human subjects before and after 10 days of cold acclimation, as well as before and after a 12-week exercise training intervention. Methods: Cold acclimation altered the expression of 756 genes (422 up, 334 down, P<0.01), while exercise training altered the expression of 665 genes (444 up, 221 down, P<0.01). Principal Component Analysis, Venn diagram, similarity analysis and Rank–rank Hypergeometric Overlap all indicated significant overlap between cold acclimation and exercise training in upregulated genes, but not in downregulated genes. Overlapping gene regulation was especially evident for genes and pathways associated with extracellular matrix remodeling. Interestingly, the genes most highly induced by cold acclimation were involved in contraction and in signal transduction between nerve and muscle cells, while no significant changes were observed in genes and pathways related to insulin signaling or glucose metabolism. Conclusions: Overall, our results indicate that cold acclimation and exercise training have overlapping effects on gene expression in human skeletal muscle, but strikingly these overlapping genes are designated to pathways related to cell remodeling rather than metabolic pathways.
Project description:Background: Cold acclimation and exercise training were previously shown to increase peripheral insulin sensitivity in human volunteers with type 2 diabetes. Although cold is a potent activator of brown adipose tissue, the increase in peripheral insulin sensitivity by cold is largely mediated by events occurring in skeletal muscle and at least partly involves GLUT4 translocation, as is also observed for exercise training. Results: To investigate if cold acclimation and exercise training overlap in the molecular adaptive response in skeletal muscle, we performed transcriptomics analysis on vastus lateralis muscle collected from human subjects before and after 10 days of cold acclimation, as well as before and after a 12-week exercise training intervention. Methods: Cold acclimation altered the expression of 756 genes (422 up, 334 down, P<0.01), while exercise training altered the expression of 665 genes (444 up, 221 down, P<0.01). Principal Component Analysis, Venn diagram, similarity analysis and Rank–rank Hypergeometric Overlap all indicated significant overlap between cold acclimation and exercise training in upregulated genes, but not in downregulated genes. Overlapping gene regulation was especially evident for genes and pathways associated with extracellular matrix remodeling. Interestingly, the genes most highly induced by cold acclimation were involved in contraction and in signal transduction between nerve and muscle cells, while no significant changes were observed in genes and pathways related to insulin signaling or glucose metabolism. Conclusions: Overall, our results indicate that cold acclimation and exercise training have overlapping effects on gene expression in human skeletal muscle, but strikingly these overlapping genes are designated to pathways related to cell remodeling rather than metabolic pathways.
Project description:To understand faster reinduction of heat acclimation, in this investigation we studied global stress associated genomic response during acclimation, following its loss and re-induction. Nylon cDNA Atlas Array was used. Collectively, the study comprised nine experimental groups of which six characterized experimental basal conditions: Controls-untreated, Short and Long term heat acclimated groups ( exposure to environmental heat at 34oC for 2 or 30 days respectively), Deacclimated group (24oC for 1mo) and Reacclimated groups (2d at 34oC following the deacclimation protocol). Three additional experimental groups: Controls, Short and Long term and Reacclimated rats (as above) were tested for genomic responses following subjection to heat stress at 41oC. Because of a dichotomy between genomic and physiological responses we hypothesize thst rapid reacclimation is linked to reprograming of gene expression. Keywords: heart, Left ventricle
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:To determine the influence of a previous physcial activity period (e.g., exercise) on global gene expression, we compared differential expression in sedentary (SED) and detrained (DETR) rats relative to trained (TR) rats with regular access to physcial activity. TR and DETR rats had voluntary access to caged running wheels for 8 and 4 weeks, respectively. DETR rats were moved to sedentary conditions (normal cage activity) for another 4 weeks. SED rats experienced 8 weeks of normal caged activity; n=8 per group. At the end of each group's respective 8 weeks, all rats underwent 1 hr of moderate of acute exercise stress (e.g., forced wheel running at a speed of 20 m/min). Soleus muscles were harvested 24h post-running.
Project description:Seventy two rats were randomized to twelve independent groups of rats (n = 6 in all groups) where half of the rats were chosen for training (treadmill exercise training 1.5 hour 5 days a week, in 1, 4, 24, 48 days and for 4 and 8 weeks) or sedentary (no training) as described in detail by Wisloff et al. (Intensity-controlled treadmill running in rats: VO(2 max) and cardiac hypertrophy. Am J Physiol Heart Circ Physiol. 2001 Mar;280(3):H1301-10.) or Kemi et al.(Aerobic fitness is associated with cardiomyocyte contractile capacity and endothelial function in exercise training and detraining. Circulation. 2004 Jun 15;109(23):2897-904. Epub 2004 Jun 1.). The rats were scarified one hour after training (1, 4, 24 and 48 days) or 24 hours after training (4 and 8 weeks). Biopsies form left ventricle was taken form all rats and stored on -80°C for preparation of RNA. The same procedures were performed for the control/sedentary rats which were sacrificed at the same time as the exercised rats.