Project description:We have previously showed that whey protein hydrolysate (WPH) causes a greater increase in muscle protein synthesis than an identical composition of amino acids mixture does. The present study was conducted to investigate a comparative effect of WPH on gene expression. Male Sprague-Dawley rats subjected to a 2-h swimming exercise were administered either a carbohydrate-amino acid diet or a carbohydrate-WPH diet immediately after exercise. One hour after exercise, epitrochlearis muscle mRNA was sampled and subjected to DNA microarray analysis. As a result, ingestion of WPH altered 189 genes in considering the false discovery rate. Among the upregulated genes, 8 Gene Ontology (GO) terms were enriched, which included key elements in muscle repair after exercise such as Cd24, Ccl2, Ccl7 and Cxcl1. On the other hand, 9 GO terms were enriched in the gene sets downregulated by ingestion of WPH and these GO terms fell into 2 clusters, 'regulation of ATPase activity' and 'immune response'. Furthermore, we found that WPH activate the 2 upstream proteins, extracellular signal-regulated kinase 1/2 (ERK1/2) and hypoxia-inducible factor-1a (HIF-1a), which may act as key factors for regulation of gene expression. These results suggest that ingestion of WPH, compared to an identical composition of amino acid mixture, induces greater changes in the after-exercise gene expression profile via activation of the proteins, ERK1/2 and HIF-1a. Male Sprague-Dawley rats (5-week-old) with body weights of approximately 150 g each (CLEA Japan, Inc., Tokyo, Japan) were used in this study. Rats were maintained at 23 +/- 2C, with lights on from 8:00 to 20:00 and off from 20:00 to 8:00. Rats had free access to food (protein 23.6%, fat 5.3%, carbohydrate 54.4%, ash 6.1%, fiber 2.9%, moisture 7.7%, MF, Oriental Yeast Co., Ltd., Osaka, Japan) and water. After 2- or 3-day acclimation, the rats were pre-trained to swimming exercise for 3 days. One day before the experiment, they were fed 5 g of a restricted diet (MF, Oriental Yeast Co., Ltd., Osaka, Japan). On the day of the experiment, rats swam for 2 hours, with 4 rats swimming simultaneously in a barrel filled with water to a depth of 50 cm, allowing an average surface area of 400 cm2 for each animal. The water temperature was maintained at a constant of 35C. Immediately following exercise, rats were given one of two isoenergetic test solutions by gavage. These solutions contained 44 kJ in a four-test dose that represented about 15% of daily energy needs and included either a mixed meal containing carbohydrate and amino acid mixture (AAM) or a mixed meal containing carbohydrate and whey protein hydrolysate (WPH; Meiji Co., Ltd., Japan). This study was approved by the Animal Committee of Food Science Research Lab., Meiji Co., Ltd., with the animals receiving care according to the guidelines laid down by this committee.

Project description:Rodents are commonly housed below thermoneutrality (~20°C) 1. Under these conditions there is a substantial effect on rodent physiology including the hyperactivation of brown (BAT) and beige adipose tissue 2. Here, we raised animals from weaning, on an obesogenic diet at thermoneutrality (28°C) to closer mimic human physiology and determine the impact of a) moderate cold exposure (i.e. 20°C, a temperature reduction of ~8°C) or b) treatment with YM-178, a highly-selective, clinically used β3-adrenoreceptor agonist on classical BAT or subcutaneous inguinal (IWAT) beige depots. Under these conditions, uncoupling protein 1 mRNA was undetectable in IWAT in all groups. Maintenance at 20°C drove weight gain and a 125% increase in subcutaneous fat, an effect not seen with YM-178 administration thus suggesting a direct effect of ambient temperature in promoting weight gain and adiposity in obese rats. Using exploratory adipose tissue proteomics we reveal novel processes and pathways associated with cold-induced weight gain in BAT (i.e. histone deacetylation and glycosphingolipid biosynthesis) and IWAT (i.e. NAD+ binding and retinol metabolism). Conversely, YM-178 had minimal metabolic-related effects on BAT and drove a pro-inflammatory phenotype in IWAT. Exercise training elicits diverse effects on brown (BAT) and white adipose tissue (WAT) physiology in rodents housed below their thermoneutral zone (i.e. 28-32°C). In these conditions, BAT is chronically hyperactive and, unlike human residence, closer to thermoneutrality. Therefore, we set out to determine the effects of exercise training in obese animals at 28°C (i.e. thermoneutrality) on BAT and WAT in its basal (i.e. inactive) state. Sprague-Dawley rats (n=12) were housed at thermoneutrality from 3 weeks of age and fed a high-fat diet. At 12 weeks of age half these animals were randomised to 4-weeks of swim-training (1 hour/day, 5 days per week). Following a metabolic assessment interscapular and perivascular BAT and inguinal (I)WAT were taken for analysis of thermogenic genes and the proteome. Exercise attenuated weight gain but did not affect total fat mass or thermogenic gene expression. Proteomics revealed an impact of exercise training on2-oxoglutarate metabolic process, mitochondrial respiratory chain complex IV, carbon metabolism and oxidative phosphorylation. This was accompanied by an upregulation of multiple proteins involved in skeletal muscle physiology suggesting an adipocyte to myocyte switch in BAT. UCP1 mRNA was undetectable in IWAT with proteomics highlighting changes to DNA binding, the positive regulation of apoptosis, HIF-1 signalling and cytokine-cytokine receptor interaction.

Project description:The adult skeletal muscle is a plastic tissue with a remarkable ability to adapt to different levels of activity by altering its excitability, its contractile and metabolic phenotype and its mass. Knowledge on the mechanisms responsible for muscle mass comes primarily from models of muscle inactivity or denervation or from genetic models of muscle diseases. Given that the underlying exercise-induced transcriptional mechanisms regulating muscle mass are not fully understood, here we investigated the cellular and molecular adaptive mechanisms taking place in fast skeletal muscle of adult zebrafish in response to swimming. Fish were trained at low swimming speed (0.1 m/s; non-exercised) or at their optimal swimming speed (0.4 m/s; exercised). A significant increase in fibre cross-sectional area (1,290 M-BM-1 88 vs. 1,665 M-BM-1 106 M-NM-<m2) and vascularization (298 M-BM-1 23 vs. 458 M-BM-1 38 capillaries/mm2) was found in exercised over non-exercised fish. Gene expression profiling evidenced the transcriptional activation of a series of complex networks of extracellular and intracellular signaling molecules and pathways involved in the regulation of muscle mass, myogenesis and angiogenesis, many (e.g. BMP, TGFM-oM-^AM-", FGF, Notch, Wnt, MEF2, Shh, EphrinB2) not previously associated with exercise-induced contractile activity, and that recapitulate in part the transcriptional events occurring during skeletal muscle regeneration. These results demonstrate that fibre hypertrophy is responsible for the growth-promoting effects of exercise accompanied by a switch to a more oxidative capacity of white muscle fibres to fuel the increased energy demands. Importantly, our study identified novel molecular mechanisms regulating muscle mass and function in vertebrates. Adult zebrafish were subjected or not to a swim training regime consisting of swimming at the optimal swimming speed for this species for 6 h/day, 5 days/week for a total of 4 weeks (20 experimental days). Total RNA of fast muscle from individual non-exercised (n = 8) and exercised (n = 8) zebrafish was analyzed.

Project description:Training at sustainable swimming speeds can produce changes in fish skeletal muscle that are important for aquaculture due to their growth-potentiating effects. Such changes may be even more relevant when fish are fed diets containing an increasing proportion of carbohydrates as an energy source. We evaluated the effects of moderate-intensity sustained swimming on the transcriptomic response of red and white muscle in rainbow trout fed a carbohydrate-rich diet using microarray and qPCR. Analysis of the red and white muscle transcriptome revealed significant changes in the expression of a large number of genes (395 and 597, respectively), with a total of 218 differentially expressed genes (DEGs) common for both muscles. A large number of the genes involved in glucose use and energy generation, contraction, development, synthesis and catabolism of proteins were up-regulated in red and white muscle. Additionally, DEGs in both muscles were involved in processes of defense response and apoptosis. Skeletal muscle contraction activates a transcriptional program required for the successful adaptation of both muscles to the changing demands imposed by swimming conditions. Future studies should further clarify the mechanisms involved in the adaptation of both tissues to exercise and assess possible benefits of such conditions for cultured fish. Total RNA from pooled red and white skeletal muscle samples of individual rainbow trout from each group (resting fish, n=8; swimming fish, n=8) was labeled with Cy3-dUTP and Cy5-dUTP (GE Healthcare, Barcelona, Spain). We used a dye swap experimental design and each cDNA from a pooled RNA sample was hybridized to two microarrays. For the first slide, cDNAs from resting and swimming fish were labeled with Cy5 and Cy3, respectively, and for the second array dye assignment was reversed. Therefore, samples from individual fish within each group were pooled and expression values shown represent the means of 6 M-CM-^W 2 = 12 technical replicates. A total of four slides were used in this study

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Microarray results from atrial tissue isolated from 6-week swimming exercised mice compared to sedentary controls

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