RNA-seq of age-associated transcriptome changes in brown adipose tissue
Ontology highlight
ABSTRACT: Brown adipose tissue (BAT) plays a central role in energy homeostasis through non-shivering thermogenesis. Besides, recent human studies using 18FDG-PET/CT imaging demonstrated that BAT acts as a significant metabolic-sink for glucose. Notably, these functions in BAT decrease with age: however what regulates this process remains poorly understood. To this end, we employed RNA-seq to identify the transcriptional changes in BAT of young and old mice.
Project description:To study the gene expression profiles of brown (BAT) and white (WAT) adipose tissues in wild type and LR11-deficeint mice. The four RNA sources, WT scWAT, Lr11 -/- scWAT, WT BAT and Lr11 -/- BAT, were prepared from subcutaneous WAT and BAT from wild-type mice and Lr11 -/- mice, respectively (n=3 each).
Project description:To assess changes in the muscle proteome that due to tumor burden and dexamethasone treatments and compare proteomic changes that occur in atrophy due to tumor burden and dexamethasone treatment with atrophy caused by aging. Regulators of muscle atrophy induced by diseases such as cancer or drugs such as dexamethasone are largely unknown. We would therefore like to determine the proteomic signature of atrophying muscle caused by tumor burden (LLC cell injected mice) and dexamethasone treatment in order to examine possible biomarkers and regulators of muscle atrophy. We would also like to compared the proteomic signature of different modes of muscle atrophy to determine similarities and differences in the possible biomarkers and regulators.
Project description:The interscapular brown adipose tissue (BAT) depots of adult male and female C57BL/6J mice, housed at 22 °C, were analyzed to identify sex differences in the BAT transcriptome at basal housing conditions.
Project description:Prdm16 is a transcription factor that drives a complete program of brown adipocyte differentiation, but the mechanism by which Prdm16 activates gene transcription remains unknown. Utilizing ChIP-seq teqhnique, we found that Prdm16 binds to chromatin at/near many brown fat-selective genes in BAT. Interestingly, Prdm16-deficiency dramatically reduced the binding of Med1 to Prdm16-target sites. Indeed, Prdm16 binds and recruits Med1 to BAT-enriched genes and the loss of Prdm16 caused a fundamental change in chromatin architecture at key BAT-selective genes and also reduced transcirptional activity. Moreover, Prdm16, through its interaction with Med1, defines and regulates the activity of super-enhancers that drive the expression of cell identity genes. Together, these data demonstrate that Prdm16 drives gene transcription by recruiting Med1 to control chromatin architecture and super-enhancers. Brown adipose tissues were collected from Prdm16 knockout and wiletype 9-month-old mice and ChIP-seq was performed for Prdm16, PolII, Med1, and H3K27ac.
Project description:We show that roscovitine; a cyclin-dependent kinases inhibitor; given to mice during the last six weeks of a 19-week high fat diet, reduced weight gain and prevented accompanying insulin resistance, hepatic steatosis, visceral adipose tissue (eWAT) inflammation and fibrosis. It also restored insulin secretion and enhanced whole body energy expenditure. Proteomics and phosphoproteomics analysis of eWAT demonstrated that Roscovitine induced a limited set of proteins associated with lipid metabolism, fatty acid oxidation metabolism and adipose tissue remodeling but suppressed expression of a larger array of peptides and phosphopeptides linked to inflammation and extracellular matrix proteins. Furthermore, the phosphoproteome analysis identified 17 putative protein kinases perturbed by roscovitine, including CMGC kinases [e.g., CDKs and MAPKs], AGC kinases [e.g., S6K and PKC isoforms], and CAMK kinases [e.g., SIK1 and SIK2]). Pathway enrichment analysis of annotated kinase-substrate pairs showed that lipid metabolism, TCA cycle, fatty acid beta oxidation and phosphatidylcholine and creatine biosynthesis are enriched following roscovitine treatment. The increased creatine pathways combined with more active mitochondria in eWAT may contribute to roscovitine-induced weight loss. Surprisingly, we found that unlike for eWAT, roscovitine led to up regulation of large sets of proteins and phosphosites in brown adipose tissue (BAT). Analysis of upstream kinases controlling the phosphoproteome revealed two major kinase groups (AGC kinases [e.g., PKD1 and PKA] and CMGC kinases [e.g., CDKs and MAPKs]. Among the top enriched pathways of kinase-substrate pairs were insulin signaling, regulation of lipolysis in adipocytes, thyroid hormone signaling, thermogenesis and cAMP-PKG signaling, suggesting that roscovitine led to a metabolically more active BAT. Overall, roscovitine treatment led to restoration of mitochondrial activity in BAT and eWAT suppressed by HFD, likely accounting for enhanced energy expenditure and weight loss.
Project description:The peroxisome proliferator-activated receptors (PPARs) are transcription factors that regulate glucose and lipid homeostasis. Activation of PPARs has been explored for the treatment of type 2 diabetes and dyslipidemia. LDT409 is a novel fatty acid like compound that has been shown to be a pan-active PPAR agonist. This data explores the changes in the liver proteome of mice treated with LDT409 while fed either a chow or high fat diet.
Project description:Adaptive thermogenesis of brown adipose tissue (BAT) is critical for thermoregulation and contributes to total energy expenditure. However, whether BAT has non-thermogenic functions is largely unknown. Here, we describe that mice with a BAT-specific Liver kinase b1 deletion (Lkb1BKO mice) exhibited impaired mitochondrial respiration and thermogenesis in BAT, but reduced adiposity and liver triglyceride accumulation under high-fat-diet feeding at room temperature. Importantly, these metabolic benefits were also present in Lkb1BKO mice at thermoneutrality, where BAT thermogenesis was not required. Mechanistically, decreased mRNA levels of mtDNA-encoded electron transport chain (ETC) subunits and ETC proteome imbalance led to impaired mitochondrial respiration in BAT of Lkb1BKO mice. Furthermore, reducing mtDNA gene expression directly in BAT by removing mitochondrial transcription factor A (Tfam) in BAT also showed ETC proteome imbalance and the tradeoff between BAT thermogenesis and systemic metabolism at both room temperature and thermoneutrality. Collectively, our data demonstrates that ETC proteome imbalance in BAT regulates systemic metabolism independently of BAT thermogenic capacity.
Project description:In this study, we aimed to study the effect of Beta-2 Adrenergic Receptor stimulation on secreted proteins in triple negative breast cancer cell lines. We also wanted to compare protein expression in parental or bone tropic metastatic cell lines and how they respond to adrenergic signaling.
Project description:The proteome cargo of extracellular vesicles released from brown adipose tissue (BAT) and from white adipose tissue (WAT) of mice subjected to cold exposure (4°C) was analysed by a TMT-based quantitative proteomic procedure in order to obtain new information on the processes of thermogenesis.
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.