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:Background: Brown and white adipose tissues (BAT and WAT) play critical roles in controlling energy homeostasis and in the development of obesity and diabetes. Fsp27 is expressed in both BAT and WAT and promotes lipid storage and the development of obesity and diabetes. In addition, Fsp27-deficient white adipocytes acquired certain BAT-like properties including reduced lipid droplet size and increased mitochondrial activity. Using microarray and semi-quantitative real-time PCR analyses, we systematically analyzed the gene expression profile in Fsp27-deficient WAT and BAT. Results: We observed that BAT-selective genes were significantly up-regulated, whereas WAT-selective genes were down-regulated in the WAT of Fsp27-/- mice. Expression levels of BAT-selective genes were also dramatically up-regulated in the WAT of leptin and Fsp27 double deficient mice. Furthermore, we observed that expression levels of genes in multiple metabolic pathways including oxidative phosphorylation, the TCA cycle and fatty acid synthesis and oxidation were increased in the Fsp27-/- WAT. In contrast, expression levels for extracellular matrix remodeling, the classic complement pathway and TGF-β signaling"were down-regulated in the WAT of Fsp27-/- mice. Most importantly, regulatory factors that determine BAT identity such as CEBPα/β, PRDM16 and major components in the cAMP pathway were markedly up-regulated in the WAT of Fsp27-/- mice. Interestingly, we observed distinct gene expression profiles in the BAT of Fsp27-/- mice. Conclusion: Our data suggest that Fsp27 acts at upstream to control gene expression of diverse pathways, in particular the expression of regulatory factors that determine the identity of BAT and WAT. Therefore, Fsp27 is an important molecular determinant for the identity of WAT, and loss of Fsp27 leads to the conversion of WAT to a BAT-like tissue. Total RNAs were extracted from individual gonadal WAT of five pairs of 3-month-old wild-type and Fsp27-null male mice. Equal amounts of RNA from five pairs of mice with each genotype were pooled to form RNA pools (total 45 μg). Duplicate experiments were carried out.

Project description:Thoracic perivascular adipose tissue (PVAT) is a unique adipose depot that likely influences vascular function and susceptibility to pathogenesis in obesity and metabolic syndrome. Surprisingly, PVAT has been reported to share characteristics of both brown and white adipose, but a detailed direct comparison to interscapular brown adipose tissue (BAT) has not been performed. Here we show by full genome DNA microarray analysis that global gene expression profiles of PVAT are virtually identical to BAT, with equally high expression of Ucp-1, Cidea and other genes known to be uniquely or very highly expressed in BAT. PVAT and BAT also displayed nearly identical phenotypes upon immunohistochemical analysis, and electron microscopy confirmed that PVAT contained multilocular lipid droplets and abundant mitochondria. Compared to white adipose tissue (WAT), PVAT and BAT from C57BL/6 mice fed a high fat diet for 13 weeks had markedly lower expression of immune cell-enriched mRNAs, suggesting resistance to obesity-induced inflammation. Indeed, staining of BAT and PVAT for macrophage markers (F4/80, CD68) in obese mice showed virtually no macrophage infiltration, and FACS analysis of BAT confirmed the presence of very few CD11b+/CD11c+ macrophages in BAT (1.0%) in comparison to WAT (31%). In summary, murine PVAT from the thoracic aorta is virtually identical to interscapular BAT, is resistant to diet-induced macrophage infiltration, and thus may play an important role in protecting the vascular bed from thermal and inflammatory stress. 8-week-old male C57BL6/J mice were fed a normal (ND) or high fat diet (HFD) (Research Diets 12451, 45 kcal% fat) for 13 weeks. Mice were then euthanized and four different adipose depots were harvested for RNA analysis: perivascular fat from the lesser curvature of the aortic arch (PVAT), interscapular brown adipose (BAT), inguinal adipose tissue (SAT), and epididymal adipose tissue (VAT). 250 ng total RNA pooled from two mice was used for cDNA synthesis; 3 biological replicates per tissue and diet were performed for a total of 24 hybridizations.

Project description:VAAM stands for an amino acid mixture simulating the composition of Vespa, a hornet larval saliva. We conducted a comparative study on metabolism-regulatory roles of VAAM, casein-simulating amino acid mixture (CAAM), and pure water on murine hepatic and adipose tissue transcriptomes. Mice were orally fed VAAM solution ( 0.675 g/ kg BW = 2% of food-derived amino acids = 0.38% of total food energy/ day), CAAM solution ( 0.675 g / kg BW/ day) or water under ad libitum for five days. Hepatic transcriptome comparison of VAAM, CAAM and water-treated groups revealed a VAAM-specific regulation of the metabolic pathway, i.e., the down-regulation of glycolysis and fatty acid oxidation, and up-regulation of poly unsaturated fatty acid synthesis and glycogenic amino acids utilization in TCA cycle. Similar transcriptomic analysis of white and brown adipose tissues (WAT and BAT) suggested the up-regulation of phospholipid synthesis in WAT and the negative regulation of cellular processes in BAT. Because these coordinated regulations of tissue transcriptomes implicated the presence of upstream signaling common to these tissues, we conducted Ingenuity Pathways Analysis of these transcriptomes with the results that estrogenic and glucagon signals seemed to be activated in liver and WAT as well as beta-adrenergic signaling did in the three tissues by administration of VAAM. Our data provide a clue to understanding the role of VAAM in metabolic regulation of multiple tissues. Mice were divided randomly into three groups, VAAM, CAAM or water administered group. VAAM, CAAM or water was orally administrated five times once a day using feeding tube. The dosage of 1.8%VAAM, 1.8%CAAM or water was 37.5 microliter per gram of body weight. On day of last administration, food was removed and mice were moved to clean cages at 8:00. The last administrations started at 10:00. At 4 hours later after last administration, mice were sacrificed by cervical dislocation to collect blood, liver, white adipose tissue (WAT) and brown adipose tissue (BAT). Small hepatic pieces were immersed into RNAlater. WAT and BAT were frozen immediately after extraction using liquid nitrogen. All samples were extracted total RNA and hybridized on Affymetrix microarrays.

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24 h-fasting effects on the brown and white adipose tissue and liver

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