Project description:The objective of this study was to identify novel genes whose expression is sensitive to androgen deprivation. We used microarrays to detail the change in gene expression within the tibialis anterior muscle following castration surgery.
Project description:Northern elephant seals (NES, Mirounga angustirostris) undergo an annual molt during which they spend ~40 days fasting on land with reduced activity and lose approximately one-quarter of their body mass. Reduced activity and muscle load in stereotypic terrestrial mammalian models results in decreased muscle mass and capacity for force production and aerobic metabolism. However, the majority of lost mass in fasting female NES is from fat while muscle mass is largely preserved. Although muscle mass is preserved, potential changes to the metabolic and contractile capacity are unknown. To assess potential changes in NES skeletal muscle during molt, we collected muscle biopsies from 6 adult female NES at the beginning of the molt and after ~30 days at the end of the molt. Skeletal muscle was assessed for respiratory capacity using high resolution respirometry, and RNA was extracted to assess changes in gene expression. Despite a month of reduced activity, fasting, and weight loss, skeletal muscle respiratory capacity was preserved with no change in OXPHOS respiratory capacity. Molt was associated with 162 upregulated genes including genes favoring lipid metabolism and regulating cell cycles. We identified 172 downregulated genes including those coding for ribosomal proteins and genes associated with skeletal muscle force transduction and glucose metabolism. Following ~30 days of molt, NES skeletal muscle metabolic capacity appears largely preserved although mechanotransduction may be compromised. In the absence of exercise stimulus, fasting-induced shifts in skeletal muscle lipid metabolism may stimulate lipid signaling pathways associated with preserving the mass and metabolic capacity of slow oxidative muscle.
Project description:Systemic administration of β-adrenoceptor (β-AR) agonists has been found to induce skeletal muscle hypertrophy and significant metabolic changes. In the context of energy homeostasis, the importance of β-AR signaling has been highlighted by the inability of β1–3-AR-deficient mice to regulate energy expenditure and susceptibility to diet induced obesity. However, the molecular pathways and gene expression changes that initiate and maintain these phenotypic modulations are poorly understood. Therefore, the aim of this study was to identify differential changes in gene expression in murine skeletal muscle associated with systemic acute administration of the β2-AR agonist formoterol. Skeletal muscle gene expression (from murine tibialis anterior) was profiled at both 1 and 4 hours following systemic administration of the β2-AR agonist formoterol, using 46K Illumina(R) Sentrix BeadArrays. Illumina expression profiling revealed significant expression changes in genes associated with skeletal muscle hypertrophy, myoblast differentiation, metabolism, circadian rhythm, transcription, histones, and oxidative stress.
Project description:Recreationally-trained college aged males underwent 10 weeks of moderate volume, high-load resistance exercise with PRE and POST vastus lateralis skeletal muscle biopsies. Protein isolation was performed on tissue samples and the sarcoplasmic protein fraction was analyzed to evaluate changes PRE to POST.
Project description:This study seeks to investigate the temporal, genome-wide response of skeletal muscle following cardiotoxin injection within the skeletal muscle of the Astyanax mexicanus – comprised of the river-dwelling surface fish and troglobitic cavefish – providing novel insights into the evolutionary consequence of skeletal muscle regernation.
Project description:Microarray analysis was performed with RNA isolated from vastus lateralis muscle biopsies of lean/overweight subjects following 18 days of aerobic exercise training. Samples from lean active individuals were also included. Exercise training led to robust changes in trained muscle. The lean active group profile was distinct from the pre-exercise samples. These results help define the molecular changes associated with aerobic training and contrast with an active phenotype.