Project description:Gene expression profiles generated from skeletal muscle biopsies taken from participants of the HERITAGE family study. Participants completed an endurance training regime in which a skeletal muscle biopsy was taken prior to the start and after the final session of the program. Biopsies were used to generate Affymetrix gene expression microarrays.
Project description:The overall objective of the heritage project is to study the role of the genotype in cardiovascular,metabolic and hormonal responses to aerobic exercise training and the contribution of regular exercise to changes in several cardiovascular disease and diabetes risk factors. The study cohort in this analysis consists of 473 Caucasian subjects (230 male and 243 female) from 99 nuclear families who completed M-bM-^IM-%58 of the prescribed 60 exercise-training sessions.The phenotypic expression of each individualM-bM-^@M-^Ys genotype is assessed under two well-defined environmental conditions, the pre- and post-training conditions. Here we have made the pre-training data available as used in the article Phillips BE, Williams JP, Gustafsson T, Bouchard C, Rankinen T, et al. (2013) Molecular Networks of Human Muscle Adaptation to Exercise and Age. PLoS Genet 9(3): e1003389. doi:10.1371/journal.pgen.1003389 52 U133+2 profiles (17M-bM-^@M-^S63 yr) generated from pre-exercise muscle biopsy samples from the HERITAGE Family Study. Heritage_pre dataset.
Project description:The overall objective of the heritage project is to study the role of the genotype in cardiovascular,metabolic and hormonal responses to aerobic exercise training and the contribution of regular exercise to changes in several cardiovascular disease and diabetes risk factors. PLEASE NOTE THE POST-TRAINING GENE CHIP FILES HAVE NEVER BEEN RELEASED ON GEO. PLEASE ALSO NOTE THAT DUE TO THE OUTDATED INSULIN ASSAY UTILISED IN THE HERITAGE STUDY, THE INSULIN DATA WAS NOT COMPARABLE WITH ANY MORE RECENT MODERN STUDIES.
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:Type 2 diabetes mellitus (DM) is characterized by insulin resistance and pancreatic beta-cell dysfunction. In high-risk subjects, the earliest detectable abnormality is insulin resistance in skeletal muscle. Impaired insulin-mediated signaling, gene expression, and glycogen synthesis, and accumulation of intramyocellular triglycerides have all been linked with insulin resistance, but no specific defect responsible for insulin resistance and DM has been identified in humans. To identify genes potentially important in the pathogenesis of DM, we analyzed gene expression in skeletal muscle from healthy metabolically characterized nondiabetic (family history negative and positive for DM) and diabetic Mexican-American subjects. We demonstrate that insulin resistance and DM associate with reduced expression of multiple nuclear respiratory factor-1 (NRF-1)-dependent genes encoding key enzymes in oxidative metabolism and mitochondrial function. While NRF-1 expression is decreased only in diabetic subjects, expression of both PPARg coactivator 1-alpha and -beta (PGC1-a/PPARGC1, and PGC1-b/PERC), coactivators of NRF-1 and PPARg-dependent transcription, is decreased in both diabetic subjects and family history positive nondiabetic subjects. Decreased PGC1 expression may be responsible for decreased expression of NRFdependent genes, leading to the metabolic disturbances characteristic of insulin resistance and DM. Human muscle samples were obtained from five subjects with type 2 diabetes and ten subjects without diabetes, as well as 5 aliquots from a single subject without diabetes. The subjects without diabetes were further classified as family history positive (four subjects) or family history negative (six subjects).
Project description:Skeletal muscle atrophy is a highly prevalent and debilitating condition that remains poorly understood at the molecular level. Previous work found that skeletal muscle atrophy involves activating transcription factor 4 (ATF4), a protein in the basic leucine zipper (bZIP) transcription factor family. However, the direct biochemical mechanism by which ATF4 promotes muscle atrophy was unknown. Because bZIP proteins such as ATF4 must dimerize to bind and activate genes, and because ATF4 is unable to form highly stable homodimers, we hypothesized that ATF4 may promote muscle atrophy by heterodimerizing with another bZIP family member. To test this hypothesis, we biochemically isolated skeletal muscle proteins that associate with the dimerization- and DNA-binding domain of ATF4 (the bZIP domain) in mouse skeletal muscle fibers in vivo. Interestingly, we found that ATF4 makes up one half of at least 5 distinct heterodimeric bZIP transcription factors in skeletal muscle fibers. This three-way interaction between ATF4, C/EBPbeta and the ATF4-C/EBP composite site activates the Gadd45a gene, which encodes a known mediator of muscle atrophy (Gadd45a). Together, these results identify a direct biochemical mechanism by which ATF4 induces skeletal muscle atrophy and provide new insight into the way that skeletal muscle atrophy occurs at the molecular level.
Project description:BACKGROUND: Histone deacetylase 4 (HDAC4) has been proposed as a target for the treatment of Amyotrophic Lateral Sclerosis (ALS) because it mediates nerve-skeletal muscle interaction and since its expression in skeletal muscle correlates with the severity of the disease. However, our recent studies on the skeletal muscle response upon long-term denervation highlighted the importance of HDAC4 in maintaining muscle integrity. METHODS: To fully identify the yet uncharacterized HDAC4 functions in ALS, we genetically deleted HDAC4 in skeletal muscles of a mouse model of ALS. Body weight, skeletal muscle, innervation and spinal cord were analyzed over time by morphological and molecular analyses. A transcriptome analysis was also performed to delineate the signaling modulated by HDAC4 in skeletal muscle of a mouse model of ALS. FINDINGS: HDAC4 deletion in skeletal muscle caused earlier ALS onset, characterized by body weight loss, muscle denervation and atrophy, and compromised muscle performance in ALS mice, although the main catabolic pathways were not activated. A transcriptome analysis identified the gene networks modulated by HDAC4 in ALS, revealing UCP1 as a top regulator that may be implicated in worsening ALS features. INTERPRETATION: HDAC4 plays an important role in preserving innervations and skeletal muscle in ALS, likely by modulating the UCP1 gene network. Our study highlights a possible risk in considering HDAC inhibitors for the treatment of ALS.