Project description:Mechanisms underlying exercise induced insulin sensitization are of interest as exercise is a clinically critical option as a lifestyle intervention for diabetic patients. Some of microRNAs (miRNAs), which can be secreted from skeletal muscle after exercise, regulate insulin sensitivity and are used for diagnostic marker for diabetic patients. MiR-204 is well-known for its involvement in development, cancer, and metabolism. However, it is still unknown whether miR-204 associates with exerciseinduced glycemic control. In preliminary data, we found that endurance exercise of mice increases miR-204 expression levels in skeletal muscle. In chronic exercise mice model, miR-204 expression levels were increased with glycolytic enzymes in skeletal muscle. When hypoxia induced hypoxia inducible factor 1 alpha (HIF1α), miR-204 expression levels were increased. HIF1α overexpression also increased miR-204 expression levels. To corroborate the causality between miR-204 and glycolysis, miR-204 mimic was introduced to myoblast cell line, C2C12 myoblast cell line. After exposure to miR-204 mimic, C2C12 cells could increase the glycolysis rate measured by extracellular acidification rate. miR-204 mimics also increased mRNA expression levels of glycolytic enzymes. In vivo intravenous miR-204 administration to mice also increased the glucose clearance rate after refeeding of mice. MiR-204 increased blood glucose surge on earlier point of refeeding but promoted the blood glucose lowering on later point of refeeding. Skeletal muscle glycolytic enzymes were increased in mRNA expression levels by miR-204 injection. This finding suggests the novel physiological role of miR-204 in skeletal muscle glycolysis where insulin action is limited.
Project description:Changes and plasticity in both gene expression and protein signaling in skeletal muscle is considered to be a major cause of metabolic syndrome, while it has been shown that mild exercise training at lactate threshold (LT) intensity is a safe and effective for prevention of metabolic syndrome. To elucidate the molecular mechanisms related to the beneficial effects of LT training for 60 min/day for 5 days/wk for 12 wk, we performed serial analysis of gene expression (SAGE) to examine global mRNA expression in human skeletal muscle. Approximately 57000 SAGE tags were analyzed for before training, as well as 5 days, 6 and 12 wk after the training. The LT training has coordinately induced many genes involved in mitochondrial energy metabolism, fat oxidation, glycolysis and creatine metabolism. Another molecular feature associated with this mild exercise regimen has been an induction of many genes encoding for potent antioxidant enzymes and molecular chaperons. Furthermore, the training modulated the expression levels of 233 novel transcripts. Thus, the current study reveals that LT exercise has favorably altered gene expression in human skeletal muscle to the prevention of metabolic syndrome. Keywords: transcriptome, serial analysis of gene expression, metabolic syndrome, exercise training, lactate threshold
Project description:The aim of this study is to discover genes regulated by miR-204. Differential gene expression in HEK-293 cells transfected with miR-204-mimic compared to HEK-293 cells transfected with control oligo (HEK-293 control) was analyzed using the Agilent Human Whole Genome 4x44K gene expression array (Agilent Technologies, Santa Clara, CA). HEK-293 cells were transfected with either miR-204 or a control, and gene expression was analyzed using the Agilent Human Whole Genome 4x44K array. A dye-swap was performed.
Project description:A single bout of exercise followed by intake of carbohydrates leads to glycogen supercompensation in the prior exercised muscle. The molecular mechanisms underlying this well-known phenomenon remain elusive. Here we report that a single bout of exercise induces marked activation of glycogen synthase (GS) and AMP-activated protein kinase (AMPK) for several days beyond normalized muscle glycogen content in man. Acute muscle specific deletion of AMPK activity in mouse muscle abrogated the ability for glycogen supercompensation, providing genetic evidence that AMPK serves as essential driver for glycogen supercompensation. Muscle proteomic analyses revealed elevated glucose uptake capacity in the prior exercised muscle while key proteins in fat oxidation and glycolysis largely remained unchanged. The temporal order of these sustained cellular alterations induced by a single bout of exercise provide a mechanism to offset the otherwise tight feedback inhibition of glycogen synthesis and glucose uptake by glycogen, ultimately leading to muscle glycogen supercompensation.
Project description:Mechanistic insights into the molecular events by which exercise enhances the skeletal muscle phenotype are lacking, particularly in the context of type 2 diabetes. Here we unravel a fundamental role for exercise-responsive cytokines (exerkines) on skeletal muscle development and growth in individuals with normal glucose tolerance or type 2 diabetes. Acute exercise triggered an inflammatory response in skeletal muscle, concomitant with an infiltration of immune cells. These exercise effects were potentiated in type 2 diabetes. In response to contraction or hypoxia, cytokines were mainly produced by endothelial cells and macrophages. The chemokine CXCL12 was induced by hypoxia in endothelial cells, as well as by conditioned medium from contracted myotubes in macrophages. We found that CXCL12 was associated with skeletal muscle remodeling after exercise and differentiation of cultured muscle. Collectively, acute aerobic exercise mounts a non-canonical inflammatory response, with an atypical production of exerkines, which is potentiated in type 2 diabetes.
Project description:The few investigations on exercise-induced global gene expression responses in human skeletal muscle haves typically focused at one specific mode of exercise and few such studies have implemented control measures. However, interpretation on distinct phenotype regulation necessitate comparison between essentially different modes of exercise and the ability to identify true exercise effects, necessitate implementation of independent non-exercise control subjects. Furthermore, muscle transkriptometranscriptome data made available through previous exercise studies can be difficult to extract and interpret by individuals that are inexperienced with bioinformatic procedures. In a comparative study, we; (1) investigated the human skeletal muscle transcriptome response to differentiated exercise and non-exercise control intervention, and; (2) aimed to develop a straightforward search tool to allow for easy extraction and interpretation of our data. We provide a simple spreadsheet containing transcriptome data allowing other investigators to see how mRNA of their interest behave in skeletal muscle following exercise, both endurance, strength and non-exercise. Our approach, allow investigators easy access to information on genuine transcriptome effects of differentiated exercise, to better aid hyporthesis-driven question in this particular field of research. 18 subjects were divided into 3 groups, performing 12 weeks of Endurance or Strength training or no training. Biopsies for microarray were take before (Pre) and 2½ and 5 hours after the last training session. Isolated RNA from these biopsies were then measured with the Affymetrix Human Gene 1.0 ST arrays.
Project description:The few investigations on exercise-induced global gene expression responses in human skeletal muscle haves typically focused at one specific mode of exercise and few such studies have implemented control measures. However, interpretation on distinct phenotype regulation necessitate comparison between essentially different modes of exercise and the ability to identify true exercise effects, necessitate implementation of independent non-exercise control subjects. Furthermore, muscle transkriptometranscriptome data made available through previous exercise studies can be difficult to extract and interpret by individuals that are inexperienced with bioinformatic procedures. In a comparative study, we; (1) investigated the human skeletal muscle transcriptome response to differentiated exercise and non-exercise control intervention, and; (2) aimed to develop a straightforward search tool to allow for easy extraction and interpretation of our data. We provide a simple spreadsheet containing transcriptome data allowing other investigators to see how mRNA of their interest behave in skeletal muscle following exercise, both endurance, strength and non-exercise. Our approach, allow investigators easy access to information on genuine transcriptome effects of differentiated exercise, to better aid hyporthesis-driven question in this particular field of research.
Project description:Unconditioned thoroughbred geldings were exercised to maximal heart rate or fatigue on an equine high-speed treadmill. Skeletal muscle biopsies were taken from the middle gluteal muscle before, immediately after and four hours after exercise. Three-condition experiment, Pre exercise (T0), Immediately post exercise (T1), 4 hours post exercise (T2). Hybridisations: T0 vs T1, T0 vs T2 Biological replicates: 8 Technical replication Dye swap
Project description:Background: Endothelial cells (ECs) use glycolysis to produce energy. In pre-clinical models of peripheral arterial disease (PAD), the further activation of EC glycolysis was ineffective and/or deleterious in promoting hypoxia-dependent angiogenesis while pentose phosphate pathway (PPP) activation was effective. Hexosamine biosynthesis pathway (HBP), PPP, and glycolysis are closely linked. Glucosamine directly activates HBP.Methods:Hind-limb ischemia (HLI)ineNOS-/-and Balb/c mice was used. Glucosamine (600 ug/g/day) was injected intraperitoneally. Blood flow recovery was assessed using laser Doppler perfusion imaging (LDPI), angiogenesis was studied by CD31immunostaining.In-vitro: human umbilical vein ECs (HUVECs) and mouse microvascular EC with glucosamine, L-glucose or vascular endothelial growth factor (VEGF165a), were tested underhypoxiaand serum starvation (HSS). Cell counting kit-8 (CCK-8), tube formation, intracellular reactive oxygen species (ROS), Electric Cell-substrate Impedance Sensing (ECIS) and FITC dextran permeability were assessed. Glycolysis and oxidative phosphorylation were assessed by seahorse assay. Gene expression was assessed using RNA sequencing, real-time qPCR, and western blot. Human muscle biopsies from patients with PAD were assessed for EC O-GlcNAcylation before and after supervised exercise vs. standard medical care. Results: Day-3 post-HLI,glucosamine vs. control-treated eNOS-/-had less necrosis.Beginning Day-7 post-HLI, glucosamine vs. control-treated Balb/chad higherblood flowthat persisted to Day-21whereischemic musclesshowed greaterCD31 staining/muscle fiber. In-vitro,glucosamine vs. L-glucoseshowedimproved EC survival and tube formation. RNA-sequencing of glucosamine vs. L-glucose showed increased amino acid metabolism. That resulted in increased oxidative phosphorylation and serine biosynthesis pathway (SBP) without an increase in glycolysis or PPP genes. This was associated with better barrier function and less ROS compared to activating glycolysis by VEGF165a. These effects were mediated by activating transcription factor 4 (ATF4); a driver of exercise-induced angiogenesis. Finally, in muscle biopsies from humans with PAD,EC/O-GlcNAcylation was increased by 12 weeks of supervised exercise vs. standard medical care. Conclusion: In-cells, mice, and humans activation of HBP by glucosamine in PAD inducesan “exercise-like” angiogenesis and offers a promising novel therapeutic pathway to treat this challenging disorder.
Project description:PAD is associated with reduced uptake of glucose and insulin resistance in skeletal muscle. In this study, we look at the effect of exercise on gene expression in patients with PAD.