Project description:Muscle mass and strength reduce during ageing with a steeper decline in women around the age of 50, which suggests that the menopausal transition is one of the mechanisms for age-induced neuromuscular deteriorations. At the moment, there is no clear explanation for the decline in muscle properties although both physical exercise and maintaining near premenopausal estrogen levels by hormonal replacement have been helpful in their preservation. However, the molecular consequences of both treatments in skeletal muscle are mostly unknown. The goal of this genome-wide study was to investigate the transcriptional networks through which power training (PT) comprising of jumping activities and estrogen containing hormone replacement therapy (HRT) may aid in the prevention of functional limitation ensued from insufficient muscle mass and physical performance after menopause. We used m. vastus lateralis samples obtained from postmenopausal women participating in a yearlong randomized double-blinded placebo-controlled trial with PT and HRT interventions. Muscle samples were available from eight PT, ten HRT and nine control women. Women in the PT group participated in a progressive PT program comprising mostly of jumping exercises for lower limbs with additional resistance exercises for the upper body. HRT intervention was double-blinded. All participants used either estradiol/noretisterone acetate preparation or placebo. Using statistical threshold p-value <0.05 and |fold change| >1.2 we identified 665 genes being differentially expressed among the studied 50-57-yr-old postmenopausal women. We used the hierarchical clustering method with extensive enrichment analysis in order to reveal enrichment of known GO or KEGG functional categories among co-regulated gene-clusters. In the enrichment analysis false discovery rate was set to be less than 15%. Transcription of “response to contraction”-, “insulin signaling”- and “adipocytokine signaling”-genes were upregulated by PT. Both PT and HRT were similarly effective on transcriptional regulation of glycolytic energy metabolism and calcium signaling. The HRT specifically affected “mitochondrion”-genes. In addition, we identified functional categories, such as “muscle development”, which were changed during the trial in all study groups. Our study revealed transcriptional changes in several functional categories in thigh muscle tissue of early postmenopausal women. The results emphasize that during the first years of the postmenopausal period, muscle properties are under transcriptional modulation, which both PT and HRT partially counteract leading to preservation of muscle mass and performance. More specifically, our findings indicate that PT and HRT may function through improving energy metabolism, improving the response to contraction, preserving functionality of mitochondria and reducing reorganization of muscle tissue. Therefore these treatments are recommended for preservation of adequate muscle mass and function. 54 samples, which formed 3 study groups with 2 timepoints, i.e., 8 power training subjects, 10 hormone replacement subjects and 9 controls. 6 control subjects had replicated samples resulting in a total of 60 hybridizations.

Project description:Muscle mass and strength reduce during ageing with a steeper decline in women around the age of 50, which suggests that the menopausal transition is one of the mechanisms for age-induced neuromuscular deteriorations. At the moment, there is no clear explanation for the decline in muscle properties although both physical exercise and maintaining near premenopausal estrogen levels by hormonal replacement have been helpful in their preservation. However, the molecular consequences of both treatments in skeletal muscle are mostly unknown. The goal of this genome-wide study was to investigate the transcriptional networks through which power training (PT) comprising of jumping activities and estrogen containing hormone replacement therapy (HRT) may aid in the prevention of functional limitation ensued from insufficient muscle mass and physical performance after menopause. We used m. vastus lateralis samples obtained from postmenopausal women participating in a yearlong randomized double-blinded placebo-controlled trial with PT and HRT interventions. Muscle samples were available from eight PT, ten HRT and nine control women. Women in the PT group participated in a progressive PT program comprising mostly of jumping exercises for lower limbs with additional resistance exercises for the upper body. HRT intervention was double-blinded. All participants used either estradiol/noretisterone acetate preparation or placebo. Using statistical threshold p-value <0.05 and |fold change| >1.2 we identified 665 genes being differentially expressed among the studied 50-57-yr-old postmenopausal women. We used the hierarchical clustering method with extensive enrichment analysis in order to reveal enrichment of known GO or KEGG functional categories among co-regulated gene-clusters. In the enrichment analysis false discovery rate was set to be less than 15%. Transcription of “response to contraction”-, “insulin signaling”- and “adipocytokine signaling”-genes were upregulated by PT. Both PT and HRT were similarly effective on transcriptional regulation of glycolytic energy metabolism and calcium signaling. The HRT specifically affected “mitochondrion”-genes. In addition, we identified functional categories, such as “muscle development”, which were changed during the trial in all study groups. Our study revealed transcriptional changes in several functional categories in thigh muscle tissue of early postmenopausal women. The results emphasize that during the first years of the postmenopausal period, muscle properties are under transcriptional modulation, which both PT and HRT partially counteract leading to preservation of muscle mass and performance. More specifically, our findings indicate that PT and HRT may function through improving energy metabolism, improving the response to contraction, preserving functionality of mitochondria and reducing reorganization of muscle tissue. Therefore these treatments are recommended for preservation of adequate muscle mass and function.

Project description:The molecular pathways that 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 wk of supervised endurance training in young sedentary males, referred to as the training-responsive transcriptome (TRT) (Timmons JA et al. J Appl Physiol 108: 1487-1496, 2010). 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 overrepresented in the TRT. In turn, miRNA profiling indicated that several miRNAs targeting RUNX1, SOX9, and PAX3 were downregulated 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, proangiogenic 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 maximal aerobic capacity (Vo(?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.

Project description:Parkinson's disease (PD) is the most common motor neurodegenerative disease, and neuromuscular function deficits associated with PD contribute to disability. Targeting these symptoms, our laboratory has previously evaluated 16-week high-intensity resistance exercise as rehabilitative training (RT) in individuals with PD. We reported significant improvements in muscle mass, neuromuscular function (strength, power, and motor unit activation), indices of neuromuscular junction integrity, total and motor scores on the unified Parkinson's disease rating scale (UPDRS), and total and sub-scores on the 39-item PD Quality of Life Questionnaire (PDQ-39), supporting the use of RT to reverse symptoms. Our objective was to identify transcriptional networks that may contribute to RT-induced neuromuscular remodeling in PD. We generated transcriptome-wide skeletal muscle RNA-sequencing in 5 participants with PD [4M/1F, 67 ± 2 years, Hoehn and Yahr stages 2 (n = 3) and 3 (n = 2)] before and after 16-week high intensity RT to identify transcriptional networks that may in part underpin RT-induced neuromuscular remodeling in PD. Following RT, 304 genes were significantly upregulated, notably related to remodeling and nervous system/muscle development. Additionally, 402 genes, primarily negative regulators of muscle adaptation, were downregulated. We applied the recently developed Pathway-Level Information ExtractoR (PLIER) method to reveal coordinated gene programs (as latent variables, LVs) that differed in skeletal muscle among young (YA) and old (OA) healthy adults and PD (n = 12 per cohort) at baseline and in PD pre- vs. post-RT. Notably, one LV associated with angiogenesis, axon guidance, and muscle remodeling was significantly lower in PD than YA at baseline and was significantly increased by exercise. A different LV annotated to denervation, autophagy, and apoptosis was increased in both PD and OA relative to YA and was also reduced by 16-week RT in PD. Thus, this analysis identified two novel skeletal muscle transcriptional programs that are dysregulated by PD and aging, respectively. Notably, RT has a normalizing effect on both programs in individuals with PD. These results identify potential molecular transducers of the RT-induced improvements in neuromuscular remodeling and motor function that may aid in optimizing exercise rehabilitation strategies for individuals with PD.

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.

Dataset Information

Power training and postmenopausal hormone therapy affect transcriptional control of specific co-regulated gene clusters in skeletal muscle.

Publications

Power training and postmenopausal hormone therapy affect transcriptional control of specific co-regulated gene clusters in skeletal muscle.

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