Transcriptional changes in skeletal muscle in response to 4 weeks of exercise training
ABSTRACT: Consequence of physical exercise in skeletal muscle was investigated in C57BL/6 mice after 4 weeks of exercise training and compared to sedentary controls. Exercised mice received four 4 weeks of regular exercise training on a motorized treadmill and were compared to sedentary controls. 6 mice of each Treatment were used to extract RNA from the quadriceps muscle three hours after the last training bout
Project description:Here we describe a genome-wide analysis of DNA-methylation in muscle of trained mice. In comparison to sedentary controls 2762 genes exhibited differentially methylated CpGs in their putative promoter regions. The majority of these genes were related to muscle growth and differentiation and a minor fraction involved in metabolic regulation. These findings suggest that DNA-methylation is involved in the regulation of muscle adaptation to regular exercise training. Reduced representation bisulfite sequencing of murine quadriceps muscle
Project description:Endurance exercise training has been shown to decrease whole-body and skeletal muscle insulin resistance and increase glucose tolerance in conditions of both pre-diabetes and overt type 2 diabetes. However, the adaptive responses in skeletal muscle at the molecular and genetic level for these beneficial effects of exercise training have not been clearly established in an animal model of pre-diabetes. The present study identifies alterations in skeletal muscle gene expression that occur with exercise training in pre-diabetic, insulin-resistant obese Zucker (fa/fa) rats and insulin-sensitive lean Zucker (Fa/-) rats. Treadmill running for up to 4 weeks caused significant enhancements of glucose tolerance as assessed by the integrated area under the curve for glucose (AUCg) during an oral glucose tolerance test in both lean and obese animals. Using microarray analysis, a set of only 12 genes was identified as both significantly altered (>1.5-fold change relative to sedentary controls; p<0.05) and significantly correlated (p<0.05) with the AUCg. Two of these genes, peroxisome proliferator-activated receptor-g coactivator 1a (PGC-1a) and the z-isoform of protein kinase C (PKC-z), have known involvement in the regulation of skeletal muscle glucose transport. We confirmed that protein expression levels of PGC-1a and PKC-z were positively correlated with the mRNA expression levels for these two genes. Overall, this study has identified a limited number of genes in soleus muscle of lean and obese Zucker rats that are associated with decreased insulin resistance and increase glucose tolerance following endurance exercise training. These findings could guide the development of pharmaceutical exercise mimetics in the treatment of insulin-resistant, pre-diabetic or overtly type 2 diabetic individuals.
Project description:Eccentric exercise (ECC) can result in ultra-structural and histological damage to skeletal muscle. The damage incurred following ECC is typically followed by a subsequent regenerative and adaptive response. The specific mechanisms that drive this response, particularly in human muscle, are not well understood. The objective of this study was to characterize the early molecular response in skeletal muscle following ECC in humans. We used an Agilent whole human genome microarray to assess global gene expression in male subjects (N=35) at 3 hours post-100 eccentric contractions of the knee extensors. ANCOVA (age and BMI covariates) was used to compare mRNA expression between the ECC and non-exercised (CON) legs of each subject. Novel transcripts from IPA identified networks were confirmed with quantitative real-time (qRT)-PCR. qRT-PCR analysis of 3 of these transcripts (IkBα, TNFRSF1A and ICAM-1) confirmed changes observed in the microarray analysis. 35 male subjects performed an eccentric exercise protocol consisting of 100 maximal eccentric contrations of the knee extensors. 3 hours after the completion of the exercise regimen, a muscle biopsy was taken from the vastus lateralis of both legs. The non-exercised leg served as the control. Gene expresssion was analyzed using an ANCOVA, with covariates for age and BMI.
Project description:Exercise training improves whole body glucose homeostasis through effects largely attributed to adaptations in skeletal muscle; however, training also affects other tissues including adipose tissue. To determine if exercise-induced adaptations to adipose tissue contribute to training-induced improvements in glucose homeostasis, subcutaneous white adipose tissue (scWAT) from trained or sedentary donor mice was transplanted into the visceral cavity of sedentary recipients. Remarkably, nine days post-transplantation, mice receiving trained scWAT had improved glucose tolerance and enhanced insulin sensitivity compared to mice transplanted with sedentary scWAT or sham-treated mice. Mice transplanted with trained scWAT had increased insulin-stimulated glucose uptake in tibialis anterior and soleus muscles and brown adipose tissue, suggesting that the transplanted scWAT exerted endocrine effects. Furthermore, the deleterious effects of high-fat feeding on glucose tolerance and insulin sensitivity were completely reversed if high-fat fed recipient mice were transplanted with trained scWAT. In additional experiments, voluntary exercise training by wheel running for only 11 days resulted in profound changes in scWAT including increased expression of ∼1550 genes involved in numerous cellular functions, including metabolism. Exercise training causes adaptations to scWAT that elicit metabolic improvements in other tissues, demonstrating a previously unrecognized role for adipose tissue in the beneficial effects of exercise on systemic glucose homeostasis. Microarray analysis of scWAT obtained from a cohort of mice that were housed in wheel cages for 11 days compared to sedentary control mice.
Project description:Exercise training increases endurance by inducing global gene expression changes in skeletal muscles. The extent to which the genetic effects of exercise can be mimicked by synthetic drugs is unknown. We measured global skeletal muscle expression in sedentary and exercised mice treated with vehicle or PPARdelta ligand GW1516. PPARdelta is a transcriptional regulator of muscle oxidative metabolism and fatigue resistance. Keywords: Pharmacology study Overall design: Sedentary and exercise trained C57Bl/6J mice were treated with vehicle or GW1516 for 4 weeks, followed by collection of quadriceps for gene expression analysis.
Project description:Transcriptome analysis of gastrocnemius muscle RNA samples from exercise and sedentary ancestries Early life and pre-conception environmental stimuli can affect adult health-related phenotypes. Exercise training is an environmental stimulus affecting many systems throughout the body and appears to alter offspring phenotypes. The aim of this study was to examine the influence of parental exercise training, or “exercise ancestry,” on morphological and metabolic phenotypes in multiple generations of mouse offspring. F0 C57BL/6 mice were exposed to voluntary exercise or sedentary lifestyle and bred with like-exposed mates to produce an F1 generation. F1 mice of both ancestries were sedentary and sacrificed at 8 wk or bred with littermates to produce an F2 generation, which was also sedentary and sacrificed at 8 wk. Small, but broad generation- and sex-specific effects of exercise ancestry were observed for body mass, fat and muscle mass, serum insulin, glucose tolerance, and muscle gene expression. F1 EX females were heavier than F1 SED females, but F1 SED females had higher absolute tibialis anterior and omental fat masses. Serum insulin was lower in F1 SED females compared to F1 EX females. F2 EX females had impaired glucose tolerance compared to F2 SED females. Analysis of skeletal muscle mRNA levels revealed several generation- and sex-specific differences in mRNA levels for multiple genes, especially those related to metabolic genes (e.g., F1 EX males had lower mRNA levels of Hk2, Ppard, Ppargc1α, Adipoq, and Scd1 than F1 SED males). These results provide preliminary evidence that parental exercise training can influence health-related phenotypes in mouse offspring. We analyzed RNA from 10 males each from exercise and sedentary ancestries over 2 generations of offspring (F1 and F2)
Project description:Exercise training increases endurance by inducing global gene expression changes in skeletal muscles. The extent to which the genetic effects of exercise can be mimicked by synthetic drugs is unknown. We measured global skeletal muscle expression in sedentary and exercised mice treated with vehicle or PPARdelta ligand GW1516. PPARdelta is a transcriptional regulator of muscle oxidative metabolism and fatigue resistance. Experiment Overall Design: Sedentary and exercise trained C57Bl/6J mice were treated with vehicle or GW1516 for 4 weeks, followed by collection of quadriceps for gene expression analysis.
Project description:Experiment designed to identify differences in gene expression patterns in previously sedentary individuals before an endurance exercise training program. This series compares 2 groups of individuals that display high and low insulin sensitivity (SI) response (HSIR and LSIR) after 20 weeks of exercise (a 4-fold difference in SI response). There were no differences before training for SI, sex, age, BMI or body fat in the individuals integrating the LSIR and HSIR groups. Keywords = skeletal muscle Keywords = exercise-training Keywords = insulin sensitivity Keywords: repeat sample
Project description:Study the training exercise effects in chronic obstructive pulmonary disease (COPD) patients and aged-matched healthy individuals. Skeletal muscle biopsies from 9 stable COPD patients with normal fat free mass index (FFMI, 21Kg/m2) (COPDN), 6 COPD patients with low FFMI (16Kg/m2) (COPL), and 12 healthy sedentary subjects (FFMI 21Kg/m2) before and after 8 weeks of a supervised endurance exercise program were analyzed. Samples were collected from open biopsies from the musculus vastus lateralis of COPD patients and healthy individuals before and after 8 weeks of exercise training. Constant-work rate exercise at 70% of pre-training Watts peak (Wpeak) (CardiO2 cycle Medical Graphics Corporation, USA) was carried out before and after 8 weeks of supervised interval training with a cycloergometer until pre-training endurance time exhaustion. Measurements before and after training were obtained at isowork-rate and iso-time.
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.