Project description:Malnutrition and low muscle mass (sarcopenia) are common problems in patients with cancer. However, a low muscle mass is associated with negative clinical outcomes in patients with cancer. Therefore, it is very important to maintain muscle mass in this population. This study aims to investigate the effect of an oral nutritional supplement on skeletal muscle mass during anti-cancer treatment.
Project description:The circadian regulation of transcriptional processes has a broad impact on cell metabolism. Here, we compared the diurnal transcriptome of human skeletal muscle conducted on serial muscle biopsies in vivo with profiles of human skeletal myotubes synchronized in vitro. Extensive rhythmic transcription was observed in human skeletal muscle in comparison to in vitro cell culture. However, nearly half of the in vivo rhythmicity was lost at the mRNA accumulation level. siRNA-mediated clock disruption in primary myotubes significantly affected the expression of ~8% of all genes, with impact on glucose homeostasis and lipid metabolism. Genes involved in GLUT4 expression, translocation and recycling were negatively affected, whereas lipid metabolic genes were altered to promote activation of lipid utilization. Moreover, basal and insulin stimulated glucose uptake were significantly reduced upon CLOCK depletion. Altogether, our findings suggest an essential role for cell-autonomous circadian clocks in coordinating muscle glucose homeostasis and lipid metabolism in humans.
Project description:The goal of this study was to define the binding sites of the core circadian factors, BMAL1 and CLOCK across the genome in adult mouse skeletal muscle. We found that mitochondrial inner-membrane genes were among the most enriched rhythmic genes via gene ontology analysis, and ChIP-Seq analysis corroborated the role of Clock and Bmal1 in targeting promoters of mitochondrial inner-membrane genes.
Project description:In utero undernutrition is associated with obesity and insulin resistance, although its effect on skeletal muscle remains poorly defined. We report that, in mice, adult offspring from undernourished dams have decreased energy expenditure, decreased skeletal muscle mitochondrial content, and altered energetics in isolated mitochondria and permeabilized muscle fibers. Strikingly, when these mice are put on a 40% calorie restricted diet they lose half as much weight as calorie restricted controls. Our results reveal for the first time that in utero undernutrition alters metabolic physiology having a profound effect on skeletal muscle energetics and response to calorie restriction in adulthood.
