Project description:Inadequate protein intake initiates an accommodative response with adverse changes in skeletal muscle function and structure. mRNA level changes due to short-term inadequate dietary protein might be an early indicator of accommodation. The aims of this study were to assess the effects of dietary protein and the diet-by-age interaction on the skeletal muscle transcript profile. Self-organizing maps were used to determine expression patterns across protein trials. 958 transcripts were differentially expressed (P<0.05) with diet and 853 had a diet-by-age interaction (P<0.05) using ANOVA. The results for diet alone revealed that P63 was associated with up-regulation of transcripts related to ubiquitin-dependent protein catabolism and muscle contraction and P63 and P94 resulted in up-regulation of transcripts related to apoptosis and down-regulation of transcripts related to cell differentiation; muscle and organ development; extracellular space; and responses to stimuli and stress. The diet-by-age expression patterns demonstrated that across the three protein trials transcripts related to protein metabolism were affected by age. Changes in skeletal muscle mRNA levels in the younger and older males to protein intake near or below the RDA are indicative of an early accommodative response. 5052 transcripts were determined as differentially expressed (P<0.05) between the younger and older males, of which 2556 met the False Discovery Rate correction (P=0.0081). The age-related changes in the transcript profile were consistent with aging skeletal muscle phenotypes including; mitochondrial dysfunction (UP- and DOWN-regulation), RNA splicing (UP), oxidative stress (UP), apoptosis (UP), and energy metabolism (DOWN). Experiment Overall Design: 22 healthy free-living younger (21-43 y, n=12) and older (63-79 y, n=10) males completed three controlled feeding trials with protein intakes of 63% (P63: 0.50 g/kg), 94% (P94: 0.75 g/kg), and 125% (P125: 1.00 g/kg) of the recommended dietary allowance (RDA). A fasting state vastus lateralis biopsy was taken from the dominant leg of each subject on day 12 of each trial following an overnight fast. Total RNA was isolated from the muscle samples using Tri-Reagent and the manufacture's protocol.

Project description:Aortic endothelia from mice exposed to dietary model of type II diabetes at 4, 6 and 8 weeks of exposure to Bio-Serv #S3282 diet. Objective: Type II diabetes is associated with endothelial dysfunction, which can contribute to accelerated atherosclerosis and subsequent cardiovascular events. We seek to identify transcripts dysregulated in vivo in response to chronic exposure to high dietary fat that leads to diabetes. Methods: Beginning at 8 weeks of age, male Tie2-GFP mice (transgenically expressing green fluorescent protein exclusively within the endothelia) were fed a 60% fat calorie diet (Bio-Serv #S3282); age-matched mice were fed normal chow. After 4, 6, and 8 weeks on the diet, aortae and skeletal muscles (gastrocnemius, biceps femoris, and plantaris) were excised, minced, and collagenolytically digested. Each tissue digest was then subjected to FACS in order to obtain 10,000 endothelial cells. Transcriptomic analyses were performed with microarrays containing the Operon Murine V4 oligo set, and highly dysregulated genes were confirmed by real-time PCR. Results: By 4 weeks, Tie2-GFP mice receiving a high fat diet exhibited a fasting glucose of 215+17 mg/dL vs. 134+23 mg/dL in controls; by 6 weeks, a high fat diet resulted in lower glucose tolerance vs. control diet. Following 4, 6, and 8 weeks of high-fat regimen, aortic endothelial transcripts up-regulated by greater than 2-fold in biologically replicate experiments included macrophage inflammatory protein 2 (Mip2), chemokine (C-C motif) ligand 9 (CCL9), galectin-3 (Gal-3), and 5-lipoxygenase-activating protein (FLAP). Endothelial transcripts up-regulated in skeletal muscle included Mip2, CCL8 and 9, FLAP, gal-1 and 3, and ferritin light chain 1 (FTL1); transcripts down-regulated in muscle included endothelin-1 (ET-1) and insulin-like growth factor II (IGF II). Discussion: Gal-3 and FTL-1 are known to increase in response to advanced glycation end-products and oxidized LDL, respectively. However, the down-regulation of ET-1 and IGFII was surprising, as the transcription of these genes has previously been thought to exacerbate atherosclerosis. In conclusion, a comprehensive analysis of the endothelial transcript-level response to a dietary model of Type II diabetes has revealed novel regulation of transcripts with roles in inflammation, insulin sensitivity, oxidative stress, and atherosclerosis. Understanding the mechanism of diabetes-associated endothelial dysfunction may lead to improved therapies that lower the risk of cardiovascular complications in diabetic patients. Each experiment is performed with a technical replicate i.e. dye reversal. there is a biological replicate of the 4 week time point

Project description:Aging animals display a decline in a multitude of physical and physiological functions, including muscle function and strength. Muscle gene expression in dogs has been evaluated for a few select genes under pathogenic or varying dietary conditions, but global gene expression profiles of aged animals has not been performed. Because the mechanisms contributing to age-related decline in muscle function are poorly defined, we used canine microarrays to compare gene expression profiles of muscle tissue from geriatric and young adult dogs. Skeletal muscle (biceps femoris) samples were collected from 6 geriatric (12 yr-old) and 6 young adult (1 yr-old) female beagles after being fed one of two diets (animal protein-based versus plant-protein based) for 12 months. RNA samples were hybridized to Affymetrix GeneChip Canine Genome Arrays. Statistical analyses indicated that age had the greatest impact on gene expression, with 262 genes differentially expressed in geriatric dogs. Although not as robust as age, diet affected mRNA abundance of 22 genes. The effect of age was most notable in genes related to metabolism, cell cycle and cell development, and transcription function, with all of these functional groups being predominantly down-regulated in older animals. The effect of diet on gene expression was mostly limited to the geriatric animals, but interactions between age and diet do not allow for a clear-cut pattern of gene expression to be observed. Keywords: age; diet Six geriatric (11.1 yr old) and 6 weanling (8 wk old) female beagles were used. Three dogs of each age were assigned to one of two dietary treatments and fed for 12 months. Diets tested in this experiment were previously shown to manipulate energy metabolism. One diet was an animal-protein based diet (APB) and was composed primarily of highly digestible ingredients and animal-derived protein and fat sources (brewerâs rice, poultry by-product meal, poultry fat) and was formulated to contain 28% protein, 23% fat, and 5% dietary fiber. The other diet was a plant-protein based diet (PPB) and was composed primarily of moderately digestible plant-derived ingredients (corn, soybean meal, wheat middlings, and meat and bone meal) and was formulated to contain 26% protein, 11% fat, and 15% dietary fiber. Although the two diets were very different in terms of ingredient and chemical composition, both were formulated to meet or exceed all nutrient requirements for canine growth according to the Association of American Feed Control Officials. Young dogs were fed ad libitum to allow for adequate growth, while geriatric dogs were fed to maintain baseline BW throughout the experiment. To produce the desired metabolic effects, the PPB diet was formulated to contain a lower caloric density (APB = 5.38 kcal/g; PPB = 4.75 kcal/g) and have a lower nutrient digestibility than the APB diet. Thus, dogs fed the PPB diet needed to consume a greater (P<0.05) quantity of food (237 g/d; 1123 kcal/d) than dogs fed the APB diet (166 g/d; 893 kcal/d) to grow (young) or maintain BW (geriatrics). Even though metabolic indices were altered, mean BW among dietary treatments was not different at any time over the course of the study for young or geriatric dogs. After 12 months on experiment, animals were fasted for 12 hr and then given a lethal dose (130 mg/kg BW) of sodium pentobarbital (Euthasol, Virbac Corp., Fort Worth, TX) intravenously into the left forearm. Death was confirmed by lack of respiration and a corneal reflex, and absence of a heartbeat detected with a stethoscope placed under the left elbow. Skeletal muscle samples were collected immediately after death was confirmed, flash frozen using liquid nitrogen, and stored at -80oC until further analysis.

Project description:Aortic endothelia from mice exposed to dietary model of type II diabetes at 4, 6 and 8 weeks of exposure to Bio-Serv #S3282 diet. Objective: Type II diabetes is associated with endothelial dysfunction, which can contribute to accelerated atherosclerosis and subsequent cardiovascular events. We seek to identify transcripts dysregulated in vivo in response to chronic exposure to high dietary fat that leads to diabetes. Methods: Beginning at 8 weeks of age, male Tie2-GFP mice (transgenically expressing green fluorescent protein exclusively within the endothelia) were fed a 60% fat calorie diet (Bio-Serv #S3282); age-matched mice were fed normal chow. After 4, 6, and 8 weeks on the diet, aortae and skeletal muscles (gastrocnemius, biceps femoris, and plantaris) were excised, minced, and collagenolytically digested. Each tissue digest was then subjected to FACS in order to obtain 10,000 endothelial cells. Transcriptomic analyses were performed with microarrays containing the Operon Murine V4 oligo set, and highly dysregulated genes were confirmed by real-time PCR. Results: By 4 weeks, Tie2-GFP mice receiving a high fat diet exhibited a fasting glucose of 215+17 mg/dL vs. 134+23 mg/dL in controls; by 6 weeks, a high fat diet resulted in lower glucose tolerance vs. control diet. Following 4, 6, and 8 weeks of high-fat regimen, aortic endothelial transcripts up-regulated by greater than 2-fold in biologically replicate experiments included macrophage inflammatory protein 2 (Mip2), chemokine (C-C motif) ligand 9 (CCL9), galectin-3 (Gal-3), and 5-lipoxygenase-activating protein (FLAP). Endothelial transcripts up-regulated in skeletal muscle included Mip2, CCL8 and 9, FLAP, gal-1 and 3, and ferritin light chain 1 (FTL1); transcripts down-regulated in muscle included endothelin-1 (ET-1) and insulin-like growth factor II (IGF II). Discussion: Gal-3 and FTL-1 are known to increase in response to advanced glycation end-products and oxidized LDL, respectively. However, the down-regulation of ET-1 and IGFII was surprising, as the transcription of these genes has previously been thought to exacerbate atherosclerosis. In conclusion, a comprehensive analysis of the endothelial transcript-level response to a dietary model of Type II diabetes has revealed novel regulation of transcripts with roles in inflammation, insulin sensitivity, oxidative stress, and atherosclerosis. Understanding the mechanism of diabetes-associated endothelial dysfunction may lead to improved therapies that lower the risk of cardiovascular complications in diabetic patients.

Project description:The underlying mechanism of how the atopic lipids in skeletal muscle affect muscle growth remains elusive. Here we chose miniature Bama swine as our model to mimick human obesity and co-associated metabolic disorders by long time diet induction and study how the atopic fat accumulation in skeletal muscle influence muscle function. After 23 months high-fat high-sucrose diet (HFHSD) fed, the model minipig model of obesity accompanied with metabolic disorders like human, and they had increased body weight and extensive lipids deposition in adipose tissues (AT) and non-AT, especially in skeletal muscle. Further more, the mass of skeletal reduced greatly and the small area (0-2000μm2) muscle reduced after diet induced. The average fiber area of Gastroc reduced 25.2%, but no significant changes appeared in the other skeletal muscles. Antioxidant capacity of skeletal muscle also reduced. Microarray profiles showed genes related to fat deposition promotion (Peroxisome proliferator activated receptor γ, CCAAT/enhancer-binding protein α and apolipoprotein E), muscle growth inhibition (myostatin and p21) up regulated, and some other muscle cell differentiation related genes (myoD) down regulated. Meanwhile, adipokines like adiponectin and 11b-hydroxysteroid dehydrogenase type 1 (11βHSD1) which partake in the crosstalk between AT and skeletal muscles rose up. We draw a clear potential crosstalk pathway that, increased 11βHSD1 secreted by excess AT will promote the expression of the major inhibitor MSTN by activating corticosterone to cortisol, leading to the growth inhibition of skeletal muscle. Overall, this research announces how obesity affects skeletal muscle growth in a crosstalk sight. Male and female Bama minipigs, aged 6 months at the start of the study, were divided into the following two groups for 23 months of treatment. Bama minipigon control (CD group, N=3) were fed standard pig chow. The experimental group (N=6) were fed high-fat high-sucrose diet (53% basal diet, 37% sucrose, 10% lard, HFHSD).

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The skeletal muscle transcript profile reflects responses to inadequate protein intake in younger and older males

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