Project description:The composition of the diet affects many processes in the body, including body weight and endocrine system. We have previously shown that dietary fat also affects the immune system. Mice fed high fat diet rich in polyunsaturated fatty acids survive S. aureus infection to a much greater extent than mice fed high fat diet rich in saturated fatty acids. Here we present data regarding the dietary effects on protein expression in spleen from mice fed three different diets, I) low fat/chow diet (LFD, n=4), II) high fat diet rich in saturated fatty acids (HFD-S, n=4) and III) high fat diet rich in polyunsaturated fatty acids (HFD-P, n=4). We performed mass spectrophotometry based quantitative proteomics analysis of isolated spleen by implementing the isobaric tags for relative and absolute quantification (iTRAQ) approach. Mass spectrometry data were analysed using Proteome Discoverer 2.4 software using the search engine mascot against Mus musculus in SwissProt. 924 proteins are identified in all sets (n=4) for different dietary effects taken for statistical analysis using Qlucore Omics Explorer software. Only 20 proteins were found to be differentially expressed with a cut-off value of false discovery rate < 0.1 (q-value) when comparing HFD-S and HFD-P but no differentially expressed proteins were found when LFD was compared with HFD-P or HFD-S. We identified a subset of proteins that showed an inverse expression pattern between two high fat diets. These differentially expressed proteins were further classified by gene ontology for their role in biological processes and molecular functions.
Project description:The beneficial effects of dietary long-chain (LC) n-3 polyunsaturated fatty acids (PUFA) in the prevention and/or treatment of some metabolic disorders result largely from their capacity to regulate the transcription level of many genes involved in metabolic and physiological homeostasis, especially in the liver. In this respect, they are known to bind and activate the Peroxisome Proliferator-Activated Receptor alpha (PPARalpha). The precursor of LC-PUFA, a-linoleic acid (ALA, C18:3 n-3) share some beneficial metabolic effects with its LC derivatives, however its role in gene regulation is poorly documented. Here, we analysed the hepatic transcriptome of mice fed for 5 weeks diets rich in either saturated FA from palm oil (PALM group) or ALA from linseed oil (LIN group). This modification of dietary fatty acid composition in a context of a high fat diet had a subtle but significant effect on the hepatic transcriptome. We identified mainly a group of genes that were upregulated in the LIN vs the PALM group and that include several well-known PPARalpha target genes involved in lipid and xenobiotic metabolism. Liver gene expression was measured in male C57BL/6J mice fed during 5 weeks a high fat diet (51% energy from fat) containing palm oil, rich in saturated fatty acids (n=10) or linseed oil, rich in 18:3 n-3 (n=8)
Project description:The prevalence of obesity has steadily increased since decades. In the meantime, in line with the exposition of populations of from industrialized countries have been exposed to fat-rich diet with high exaggerated ù6/ù3 ratio of ù6- over ù3-polyunsaturated fatty acids. To assess the contribution of dietary fatty acids, male and female mice fed a human-like fat diet were mated randomly and maintained after breeding on the same diet for successive generations. Offspring showed over 4 generations a gradual enhancement in fat mass due to combined hyperplasia and hypertrophy with no change in energy intake. Transgenerational alterations in adipokine levels were accompanied by hyperinsulinemia. When switched to a standard diet, the obese phenotype (termed revHF4) reversed partially. Offspring of revHF4 mice exhibited higher birth weight and faster gain weight compared to control mice. Gene expression analyses of the stromal vascular fraction of adipose tissue over generations revealed i) underexpression of genes favoring angiogenesis and controlling oxidative stress and ii) overexpression of genes involved in inflammation, and in adipogenesis .and in insulin resistance. Thus, under conditions of genome stability, our results show that metabolic imprinting induced by a human-like fat diet is accompanied by a gradual fat mass enhancement, in accordance with the increasing prevalence of obesity observed in humans over generations.
Project description:Dietary polyunsaturated fatty acids (PUFA) act as potent natural hypolipidemics and are linked to many health benefits in humans and in animal models. Mice fed long-term a high fat diet, in which medium-chain alpha linoleic acid (ALA) was partially replaced by long-chain docosahexaenoic (DHA) and eicosapentaenoic (EPA) fatty acids, showed reduced accumulation of body fat and prevention of insulin resistance, besides increased mitochondrial beta-oxidation in white adipose tissue and decreased plasma lipids. ALA, EPA and DHA all belong to PUFA of n-3 series. The intestine is a gatekeeper organ for ingested lipids. To examine the potential contribution of the intestine in the beneficial effects of EPA and DHA, this study assessed gene expression changes using whole genome microarray analysis on small intestinal scrapings. The main biological process affected was lipid metabolism. Fatty acid uptake, peroxisomal and mitochondrial beta-oxidation, and omega-oxidation of fatty acids were all increased. Quantitative real time PCR and intestinal fatty acid oxidation measurements ([14C(U)]-palmitate) confirmed significant gene expression differences in a dose-dependent manner. Furthermore, no major changes in the expression of lipid metabolism genes were observed in colonic scrapings. In conclusion, we show that marine n-3 fatty acids regulate small intestinal gene expression patterns. Since this organ contributes significantly to whole organism energy use, this adaptation of the small intestine may contribute to the complex and observed beneficial physiological effects of these natural compounds under conditions that will normally lead to development of obesity and diabetes. Experiment Overall Design: Male 4-month-old C57BL/6J mice were maintained for 4 weeks on semisynthetic high-fat (20% wt/wt) diets differing in the composition of n-3 PUFA. Two isocaloric diets were used (n=12): control sHFf diet which contained flax-seed oil (rich in ALA) as the only lipid source, or the sHFf-F2 diet, which had the same composition except that 44 % of the lipids were replaced by a n-3 PUFA concentrate (EPA&DHA) containing 6 % EPA and 51 % DHA (EPAX 1050TG; EPAX AS, Lysaker, Norway). Quality control of RNA samples showed that four samples did not pass quality thresholds, and these samples were excluded from array analysis (two control small intestine samples and one EPA&DHA small intestine sample). The remaining RNA samples were pooled per tissue per diet group. Thus; the flax-seed (control) array was hybridized with RNA pooled from of 10 mice, the PUFA array was hybridized with RNA pooled from 11 mice.
Project description:Stearoyl-CoA desaturase 1-deficient (SCD1-/-) mice have impaired monounsaturated fatty acid (MUFA) synthesis. When maintained on a very low-fat, high-carbohydrate (VLF-HC) diet, SCD1-/- mice develop severe hypercholesterolemia characterized by an increase in apolipoprotein B-containing lipoproteins and the appearance of lipoprotein-X. Additionally, high-density lipoprotein cholesterol is dramatically reduced in VLF-HC SCD1-/- mice. The concomitant presence of elevated plasma bile acids, bilirubin and aminotransferases in the VLF-HC SCD1-/- mouse are indicative of hepatic dysfunction. Supplementation of the VLF-HC diet with unsaturated fat (canola oil), but not saturated fat (coconut oil), prevents these plasma phenotypes. However, dietary oleate was not as effective as canola oil in reducing low-density lipoprotein cholesterol, signifying an additional role for dietary polyunsaturated fatty acid deficiency in the development of this phenotype. These results indicate that lack of SCD1 results in an increased requirement for dietary unsaturated fat to compensate for impaired MUFA synthesis and to prevent hypercholesterolemia and hepatic dysfunction. Experiment Overall Design: We used Affymetrix Mouse430v2.0 microarray chips to search for gene expression changes unique to the VLF-HC SCD1-/- group. These chips contain 45,101 probe sets representing over 39,000 transcripts and variants from over 34,000 mouse genes. We studied SCD1+/+ and SCD1-/- mice on chow or the VLF-HC diet, analyzing five individual livers from each subgroup for a total of twenty microarrays.
Project description:Stearoyl-CoA desaturase 1-deficient (SCD1-/-) mice have impaired monounsaturated fatty acid (MUFA) synthesis. When maintained on a very low-fat, high-carbohydrate (VLF-HC) diet, SCD1-/- mice develop severe hypercholesterolemia characterized by an increase in apolipoprotein B-containing lipoproteins and the appearance of lipoprotein-X. Additionally, high-density lipoprotein cholesterol is dramatically reduced in VLF-HC SCD1-/- mice. The concomitant presence of elevated plasma bile acids, bilirubin and aminotransferases in the VLF-HC SCD1-/- mouse are indicative of hepatic dysfunction. Supplementation of the VLF-HC diet with unsaturated fat (canola oil), but not saturated fat (coconut oil), prevents these plasma phenotypes. However, dietary oleate was not as effective as canola oil in reducing low-density lipoprotein cholesterol, signifying an additional role for dietary polyunsaturated fatty acid deficiency in the development of this phenotype. These results indicate that lack of SCD1 results in an increased requirement for dietary unsaturated fat to compensate for impaired MUFA synthesis and to prevent hypercholesterolemia and hepatic dysfunction. Keywords: repeat (genotype and diet)
Project description:The current study was designed to determine if dietary fatty acid concentration and composition affects the development and progression of nonalcoholic fatty liver disease. Male SD rats were overfed diets low (5%) or high (70%) fat diets via total enteral nutrition where the fat source was olive oil (monounsaturated), or corn oil (polyunsaturated). Overfeeding 5% corn oil produced little steatosis relative to feeding 5% olive oil. This was associated with lower fatty acid synthesis and reduced SREBP-c signaling in the 5% corn oil group. Overfeeding 70% fat diets increased steatosis and lead to increased liver necrosis in the 70% corn oil but not olive oil group. Increased injury after feeding polyunsaturated fat diets was linked to peroxidizability of hepatic free fatty acids and triglycerides and appearance of peroxidaized lipid products HETES and HODES previously linked to clinical nonalcoholic steatohepatitis. Male SD rats were overfed diets low (5%) or high (70%) fat diets via total enteral nutrition where the fat source was olive oil (monounsaturated) or corn oil (polyunsaturated).
Project description:Long-term consumption of fatty foods is associated with obesity, macrophage activation and inflammation, metabolic imbalance, and a reduced lifespan. We took advantage of Drosophila genetics to investigate the role of macrophages and the pathway(s) that govern their response to dietary stress. Flies fed a lipid-rich diet presented with increased fat storage, systemic JAK-STAT activation, reduced insulin sensitivity and hyperglycaemia, and a shorter lifespan. Drosophila macrophages scavenged lipids and produced the type 1 cytokine upd3, in a scavenger-receptor (croquemort) and JNK-dependent manner. Genetic depletion of macrophages, or macrophage-specific silencing of upd3 decreased JAK-STAT activation and rescued insulin sensitivity and the lifespan of Drosophila, but did not decrease fat storage. NF-M-NM-:B signalling made no contribution to the phenotype observed. These results identify an evolutionarily conserved M-bM-^@M-^Xscavenger receptor-JNK-Type 1 cytokineM-bM-^@M-^Y cassette in macrophages, which controls glucose metabolism and reduces lifespan in Drosophila maintained on a lipid-rich diet via activation of the JAK-STAT pathway Long-term consumption of fatty foods is associated with obesity, macrophage activation and inflammation, metabolic imbalance, and a reduced lifespan. We took advantage of Drosophila genetics to investigate the role of macrophages and the pathway(s) that govern their response to dietary stress. Flies fed a lipid-rich diet presented with increased fat storage, systemic JAK-STAT activation, reduced insulin sensitivity and hyperglycaemia, and a shorter lifespan. Drosophila macrophages scavenged lipids and produced the type 1 cytokine upd3, in a scavenger-receptor (croquemort) and JNK-dependent manner. Genetic depletion of macrophages, or macrophage-specific silencing of upd3 decreased JAK-STAT activation and rescued insulin sensitivity and the lifespan of Drosophila, but did not decrease fat storage. NF-M-NM-:B signalling made no contribution to the phenotype observed. These results identify an evolutionarily conserved M-bM-^@M-^Xscavenger receptor-JNK-Type 1 cytokineM-bM-^@M-^Y cassette in macrophages, which controls glucose metabolism and reduces lifespan in Drosophila maintained on a lipid-rich diet via activation of the JAK-STAT pathway 5 biological samples were FACS-sorted from different batches of Drosophila melanogaster males after 30 days on 15% lipid enriched diet (n=5) and control diet (n=5)
Project description:The pathogenesis of non-alcoholic fatty liver disease (NAFLD) is associated with abnormalities of liver lipid metabolism, especially with the accumulation of saturated fatty acids (FA). On the contrary, a diet enriched with n-3 polyunsaturated FA (n-3-PUFA) has been reported to ameliorate the progression of NAFLD. The aim of our study was to investigate the impact of dietary n-3-PUFA enrichment on the development of NAFLD and liver lipidome. Mice were fed for 6 weeks either high-fat methionine choline-deficient diet (MCD) or standard chow (two groups fed MCD, two control groups, both with or without n-3-PUFA). Genome-wide transcriptome analysis of liver tissue was performed and revealed differences in liver mRNA transcriptomes after MCD as well as n-3-PUFA administration.
Project description:Transcriptome analysis of total RNA from C57BL/6 epididymal adipose tissue samples Exogenously administered glucocorticoids (GC) are used for the treatment of numerous pathologies, however their chronic usage is associated with alterations in lipid metabolism and adipose tissue function. The combination of chronic GC usage with consumption of a high fat diet poses an even greater risk for the development of adverse metabolic outcomes. We evaluated the effect of chronic GC usage in combination with a 45% high fat diet rich in n-6 polyunsaturated fatty acids (PUFA) on visceral adipose tissue gene expression in C57BL/6 male mice.