Project description:Comparative transcriptomic analysis: dietary treatment, genetic selection, and muscle fat content We used fish from two divergent lines of rainbow trout, selected for low or high muscle fat content (respectively L and F lines) and fed two different diets, containing either 10% (LE diet) or 23% (HE diet) lipids. For more details about experimental fish and diets, see Kolditz et al., Am J Physiol Regul Integr Comp Physiol 294: R1154âR1164, 2008. There are 4 experimental conditions: L-LE, L-HE, F-LE and F-HE. This experiment contain the data derived from the hybridization of the RNA extracted from individual muscle of these fish. For each membrane, spots with an oligonucleotide signal lower than three times the background level were excluded from the analysis. After this filtering step, signal processing was performed using the vector oligonucleotide data to correct each spot signal according to the actual amount of DNA present in each spot. After correction, the signal was normalized by dividing each gene expression value by the median value of the array. The study consisted of 19 samples total.
Project description:Introduction. Many investigators have attempted to define the molecular nature of changes responsible for insulin resistance in muscle, but a molecular approach may not consider the overall physiological context of muscle. Because the energetic state of ATP (ΔGATP) could affect the rate of insulin-stimulated, energy-consuming processes, the present study was undertaken to determine whether the thermodynamic state of skeletal muscle can partially explain insulin sensitivity and fuel selection independently of molecular changes. Methods. 31P-MRS was used with glucose clamps, exercise studies, muscle biopsies and proteomics to measure insulin sensitivity, thermodynamic variables, mitochondrial protein content, and aerobic capacity in 16 volunteers. Results. After showing calibrated 31P-MRS measurements conformed to a linear electrical circuit model of muscle nonequilibrium thermodynamics, we used these measurements in multiple stepwise regression against rates of insulin-stimulated glucose disposal and fuel oxidation. Multiple linear regression analyses showed 53% of the variance in insulin sensitivity was explained by 1) VO2max (P = 0.001) and the 2) slope of the relationship of GATP with the rate of oxidative phosphorylation (P = 0.007). This slope represents conductance in the linear model (functional content of mitochondria). Mitochondrial protein content from proteomics was an independent predictor of fractional fat oxidation during mild exercise (R2 = 0.55, P = 0.001). Conclusions. Higher mitochondrial functional content is related to the ability of skeletal muscle to maintain a greater GATP, which may lead to faster rates of insulin-stimulated processes. Mitochondrial protein content per se can explain fractional fat oxidation during mild exercise.
Project description:Background The composition of intramuscular fat depends on genetic and environmental factors, including the diet. In pigs, we identified a haplotype of three SNP mutations in the steaoryl-coA desaturase (SCD) gene promoter associated with higher content of monounsaturated fatty acids in intramuscular fat. The second of these three SNPs (rs80912566, C>T) affected a putative retinol response element in the SCD promoter. The effect of dietary vitamin A restriction over intramuscular fat content is controversial in pigs as it seems to depend on the genetic line and the duration of the restriction. This study aims to investigate changes in the muscle transcriptome in SCD rs80912566_TT and CC pigs fed with and without vitamin A supplement during the fattening period. Results Vitamin A did not affect carcass fattening traits and fatty acid composition in muscle, but we observed an interaction between vitamin A and SCD genotype on the desaturation of muscle fatty acids. The diet without vitamin A supplement tended to enlarge the compositional differences between genotypes. The interaction between diet and genotype was also evident at the transcriptome level, the highest number of differentially expressed genes were detected between SCD rs80912566_TT pigs fed with the two diets. Conclusions Restricting dietary vitamin A during the fattening period did not improve intramuscular fat content despite relevant changes in muscle gene expression, both in coding and non-coding genes. Despite this, there was a significant interaction between the SCD genotype and the dietary vitamin A, which affected the quality of the meat through a change in the saturation index of intramuscular fat and activated general pathways of retinol response in a SCD genotype-dependant manner.
Project description:we collected tissues of subcutaneous fat and longissimus dorsi (LD) muscle from individuals that have divergent of backfat thickness and intramuscular fat content, and have similar age and body weight. The transcriptomic and proteomic data were gained using RNA-Seq and TMT to identify the key genes and pathways that specifically regulate the subcutaneous fat and intramuscular fat deposition in Dingyuan pig.
Project description:Intramuscular fat (IMF) content is one of the key factors affecting meat quality. Carbohydrate response element binding protein (ChREBP) can promote glucose metabolism and fat synthesis by activating the expression of glycolysis and lipogenesis-related genes, but its function and regulatory mechanism in IMF are still unclear. This study evaluated the correlation between TG content and ChREBP expression level in muscles of different species to reveal the relationship between ChREBP and IMF. RNA-seq analysis showed that overexpressing ChREBP in C2C12 cells can significantly up-regulate fatty acid synthesis pathways, while significantly down-regulate the expression levels of muscle development pathways and related genes. In vivo, we found that overexpression of ChREBP or activation by fructose significantly increased the triglyceride content of the tibialis anterior muscle (TA) and the IMF content of yellow feather chicken leg and breast muscle in mice. And lipidomics data also found that feeding fructose can change the lipid composition of yellow feather broiler breast muscle and improve the flavor substances. This study demonstrated that ChREBP is a key gene regulating IMF deposition, providing a new target for genetic selection and nutritional regulation of IMF content.
Project description:Background: Marketing products with added-value characteristics is a current trend in livestock production systems. Regarding meat, selection for intramuscular fat and muscular fatty acid composition is a way to improve the palatability and juiciness of meat while assuring a healthy fat content. This represents selecting animal with a different muscular metabolic profile with respect to the extended selection of lean animals. Results: The present study has analysed the muscular gene expression profiles of 68 commercial Duroc pigs belonging to two groups with extreme phenotypes for traits strongly related with lipid deposition and composition. This has allowed us to compare the physiological and metabolic implications of selecting for each of these extreme groups. Rather than upregulation of a single pathway, the main differences lied on the transcriptional levels of genes related with lipogenesis and lipolysis, revealing the existence of a cycle where triacylglycerols are continuously synthesized and degraded. Most strikingly, several genes which enhanced fatty acid β-oxidation and favoured insulin signalling and glucose uptake were upregulated in the fattest animals, indicating that the events leading to peripheral insulin resistance in humans with increased levels of intramuscular fat and obesity do not take place in these pigs. Moreover, neither was detected the well-characterised low-grade inflammatory state observed in overweighed humans. Conclusion: As a whole, our data suggest that selection for increasing intramuscular fat content in pigs would lead to a shift but not a disruption of the metabolic homeostasis of muscle cells. Future studies on the post-translational changes affecting protein activity or expression as well as information about protein location within the cell would be needed to fully understand how lipid deposition affects muscle physiology in pigs. 68 gluteus medius samples form 68 animals belonging to two groups of 34 animals each: HIGH group had higher carcass, plasma and muscle fat content; LOW group had lower carcass, plasma and muscle fat content
Project description:Prolonged intervention studies investigating molecular metabolism are necessary for a deeper understanding of dietary effects on health. Here we provide mechanistic information about metabolic adaptation to fat-rich diets. Healthy men ingested saturated (SFA) or poly unsaturated (PUFA) fat-rich diets for six weeks during weight maintenance. Hyperinsulinemic clamps combined with leg balance technique revealed unchanged peripheral insulin sensitivity, independent of fatty acid type. Both diets increased fat oxidation potential in muscle. Hepatic insulin clearance increased, while glucose production, de novo lipogenesis and plasma triacylglycerol decreased. High fat intake changed the plasma proteome in immune-supporting direction and the gut microbiome displayed changes at taxonomical and functional level with PUFA. In mice, eucaloric feeding of human PUFA and SFA diets lowered hepatic triacylglycerol content compared to low-fat fed control mice, and induced adaptations in the liver supportive of decreased gluconeogenesis and lipogenesis. Intake of fat-rich diets thus induces extensive metabolic adaptations enabling disposition of dietary fat without metabolic complications.
Project description:Using mass spectrometry-based phosphoproteomics, we quantified 23,126 phosphosites in the skeletal muscle of five genetically distinct inbred mouse strains exposed to two controlled dietary environments, with and without acute insulin treatment. Almost half of the insulin-regulated phosphoproteome was altered by genetic background independently of diet, and high-fat high-sugar feeding also affected insulin signalling in a strain-dependent manner. Our data illuminated signalling network organisation principles, including the uncoupling of phosphosites targeted by the same kinase. Associating diverse signalling responses with insulin-stimulated glucose uptake uncovered regulators of muscle insulin responsiveness, including the regulatory phosphosite S469 on Pfkfb2, a key glycolytic enzyme.
Project description:The present work emplyed pigs as an animal model for recognition of molecular processes associated with fat deposition. The transcriptomic changes dependent on fat content were showed at the fat and liver levels. In the experiment Złotnicka White pigs were used that were not under selection pressure, because they are included in to National Preservation Program.
Project description:Transcriptional profiling in skeletal muscle of 48 pigs (132 days of age) originated from two lines divergently selected for residual feed intake (RFI) : low-RFI pigs (RFIneg), high-RFI pigs (RFIpl). Both lines were offered isocaloric and isoproteic diets with contrasted energy source and nutrients: low fat, low fiber (LF) diet or a high fat, high fiber (HF)diet during 10 weeks. Effects of RFI selection, diet and interaction between diet and line were investigated.