Project description:Endurance-trained athletes have high oxidative capacity, enhanced insulin sensitivity, and high intracellular lipid accumulation in muscle. These characteristics are likely due to altered gene expression levels in muscle. We used microarrays to detect gene expression profile in endurance-trained athlete skeletal muscle.
Project description:Low-carbohydrate diets enhance lipid metabolism and decrease reliance on glucose oxidation in athletes, but the associated gene expression patterns remain unclear. To provide mechanistic insight, we investigated the skeletal muscle transcriptome in elite ultra-endurance athletes habitually consuming a high-carbohydrate (HC, n=10, 33±6y, VO2max=63.4±6.2 mL O2•kg-1•min-1) or low-carbohydrate (LC, n=10, 34±7y, VO2max=64.7±3.7 mL O2•kg-1•min-1) diet. Skeletal muscle gene expression was measured at baseline (BL), immediately-post (H0), and 2h (H2) after 3h submaximal treadmill running. Exercise induced a coordinated but divergent expression pattern. LC had higher expression of genes associated with lipid metabolism, particularly at BL. At H2, gene expression patterns were associated with differential pathway activity, including inflammation/immunity, suggesting a diet-specific influence on early muscle recovery. These results indicate that a habitual ketogenic diet leads to differences in resting and exercise-induced skeletal muscle gene expression patterns, underlying our previous findings of differential fuel utilization during exercise in elite male ultra-endurance athletes.
Project description:Advances in mass-spectrometry (MS)-based technologies have leveraged our understanding of protein-wide adaptations in human skeletal muscle in response to exercise. However, there is a lack of such data in females, particularly pertaining to already trained females and menstrual cycle phase-based sprint interval training (SIT) despite its efficacy and popularity. Here, we present a comprehensive global proteome analysis of skeletal muscle adaptations to high-frequency SIT during different menstrual cycle phases in endurance-trained females. We randomized 49 eumenorrheic females to either high-frequency SIT in the follicular (FB) or luteal phase (LB) over one menstrual cycle comprising eight sessions of 6×30-s all-out efforts. MS-proteomics, covering 4155 proteins after filtering, revealed notable differences in muscle adaptations to phase-based SIT. LB suppressed mitochondrial pathways of the tricarboxylic acid cycle and electron transport chain while enriching ribosomal complexes. Conversely, FB enriched filament organization and skeletal system development. Mitochondrial repression during LB was linked to reduced O2max, whereas exercise capacity improved in FB only. Our findings show that menstrual cycle phase-based high-frequency SIT induces distinct protein-wide muscle adaptations and affects phenotype in endurance-trained eumenorrheic females.
Project description:Impact of protein ingestion following 1 h intense cycling on the induced transcriptome and signaling in biopsy samples from endurance-trained men, relative to isocaloric control Single blind, randomized, crossover design comprising two experimental blocks. During the blocks, exercise and diet were controlled and the intervention consisted of the ingestion of a protein-enriched and control beverage, with outcome measures obtained from skeletal muscle tissue collected following a bout of intense cycling. Total RNA were obtained from quadriceps. Each of the two serves were isocaloric and provided 0.2 g/kg fat (freeze dried canola oil) with either 1.2 g/kg carbohydrate (1:1 maltodextrin:fructose) and 0.4 g/kg protein (2:1 milk protein concentrate:whey isolate); or 1.6 g/kg carbohydrate (1:1 maltodextrin:fructose).
Project description:We examined global mRNA expression using cDNA microarrays in skeletal muscle of humans before, and 3h and 48h after a single bout of exhaustive endurance exercise (cycling). Keywords: Time course Healthy, non-trained university-aged subjects performed a single bout of exhaustive cycling. Skeletal muscle biopsies were taken from the vastus lateralis before, 3h and 48h after the exercise bout. Total RNA was extracted, amplified, reverse transcribed, and cDNA was analyzed on a custom made cDNA microarray. Four subjects were analyzed, and samples were not pooled between subjects (i.e. individual microarrays were used for baseline vs. 3H and baseline vs. 48h for EACH subject; repeated measures design).
Project description:Skeletal muscle has an enormous plastic potential to adapt to various external and internal perturbations. While morphological changes in endurance trained muscles are well described, the molecular underpinnings of training adaptation are poorly understood. We aimed at defining the molecular signature of a trained muscle and unraveling the training status-dependent responses to an acute bout of exercise. Our results reveal that even though at baseline, the transcriptomes of trained and untrained muscles are very similar, training status substantially affects the transcriptional response to an acute challenge, both quantitatively and qualitatively, in part mediated by epigenetic modifications. Second, proteomic changes were elicited by different transcriptional modalities. Finally, an unexpected resilience to enhance endurance performance even in the absence of key regulatory factors was observed, suggesting a strong evolutionary pressure on enabling muscle plasticity even in unfavorable contexts. Together, these results provide a molecular framework that defines muscle plasticity in training.
Project description:We used gene microarray analysis to compare the global expression profile of genes involved in adaptation to exercise training in skeletal muscle from chronically strength/resistance trained (ST), endurance trained (ET) and untrained control subjects (Con). Resting skeletal muscle samples (~100mg) were obtained from the vastus lateralis of 20 subjects (Con n=7, ET n=7, ST n=6; trained groups >8 years specific training). Total RNA was extracted from tissue and microarrays completed, with test samples compared with standard human reference RNA. Subjects were characterised by performance measures of maximal oxygen uptake (VO2max) on a cycle ergometer and maximal concentric and eccentric leg strength on an isokinetic dynamometer. 263 genes were differentially expressed in trained (TR collectively ET + ST) subjects compared with Con (P<0.05) while 21 genes were different between ST and ET (P<0.05). Manual cluster analyses revealed significant regulation of genes involved in muscle structure and development in TR subjects compared with Con (P<0.05), and expression of these correlated significantly with measures of performance (P<0.05). ET had increased and ST decreased expression of gene clusters related to mitochondrial/oxidative capacity (P<0.05), and these mitochondrial gene clusters correlated significantly with VO2max (P<0.05). VO2max also correlated with expression of gene clusters that regulate fat and carbohydrate oxidation (P<0.05). We have demonstrated that chronic training has marked effects on basal gene expression by regulating levels of multiple mRNAs that transcribe genes for important functional groups in human skeletal muscle. Some specific gene clusters are expressed regardless of the training stimulus, whereas others exhibit divergent expression patterns as a result of specific training stimuli. Keywords: Comparative, cluster analysis, endurance training, strength training, muscle phenotype This was a crossectional study examining basal gene expression profiles of the human vastus lateralis. Twenty healthy males volunteered for this investigation. Seven were endurance trained cyclists (ET), who had been participating in endurance training for 8 yr. These subjects had no history of resistance training. Six subjects were strength trained power-lifters (ST) who had been participating exclusively in strength/resistance training for 9 yr. The final seven subjects were healthy controls (CON) that did not participate in any formal exercise. The study was approved by the Human Research Ethics Committee of RMIT University and Monash University Standing Committee on Ethics Research on Humans. After RNA extraction, amplification and indirect labelling, a dual colour micro-array analysis was conducted by hybridizing a test (muscle RNA; Cy5) sample and a reference (Universal human RNA; Cy3) sample on the AGRF glass slide human 8K micro-array. After data capture with the Genepix scanner and associated software data was normalised and the three populations compared using GeneSpring and simplified cluster analysis.
Project description:Aging is associated with mitochondrial dysfunction and insulin resistance. We conducted a study to determine the role of long-term vigorous endurance exercise on age-related changes in insulin sensitivity and various indices of mitochondrial functions. Experiment Overall Design: Skeletal muscle transcript profiling was done using Vastus Lateralis muscle biopsy samples from 10 young sedentary (YS), 10 older sedentary (OS), 10 young trained (YT) and 10 older trained (OT) men and women. Note that YT2, YS1, and OT1 didn't pass the Quality Control Step of dChip (high array/single outliers). Sedentary subjects exercised less than 30 min/day, twice per week. Trained subjects performed ⥠1 hour cycling or running 6 days/week over the past 4 years.
Project description:Analysis of the changes in the transcriptome of circulating neutrophils and skeletal muscle from standardized resting conditions (baseline; pre-EXTRI) to 3, 48 and 96 hours after an experimental exercise trial (EXTRI; 1 hour of cycling followed by 1 hours of running) in 8 healthy, endurance-trained, male subjects. It was hypothesized that the time-course dependent transcriptomic changes would reflect the molecular and signalling mechanisms by which neutrophils regulate and counter-regulate inflammation, and by which skeletal muscle responds, regenerates, and phenotypically adapts to intense, prolonged exercise involving muscle damage. Results provide an important insight in the signalling pathways underlying the transcriptional activation and priming of circulatory neutrophils in response to physiological stress, in particular muscle-derived damage-associated molecular patterns. Furthermore, the study provides novel data on the skeletal muscle transcriptome beyond 48 hours after strenuous endurance exercise, and indicates important muscular remodelling processes at 96 hours post-EXTRI. Blood and muscle samples were taken under standardized conditions at baseline (pre-EXTRI), and 3, 48 and 96 hours post-EXTRI. Total mRNA was extracted from isolated neutrophils, and from skeletal muscle tissue.
Project description:Analysis of the changes in the transcriptome of circulating neutrophils and skeletal muscle from standardized resting conditions (baseline; pre-EXTRI) to 3, 48 and 96 hours after an experimental exercise trial (EXTRI; 1 hour of cycling followed by 1 hours of running) in 8 healthy, endurance-trained, male subjects. It was hypothesized that the time-course dependent transcriptomic changes would reflect the molecular and signalling mechanisms by which neutrophils regulate and counter-regulate inflammation, and by which skeletal muscle responds, regenerates, and phenotypically adapts to intense, prolonged exercise involving muscle damage. Results provide an important insight in the signalling pathways underlying the transcriptional activation and priming of circulatory neutrophils in response to physiological stress, in particular muscle-derived damage-associated molecular patterns. Furthermore, the study provides novel data on the skeletal muscle transcriptome beyond 48 hours after strenuous endurance exercise, and indicates important muscular remodelling processes at 96 hours post-EXTRI.