Active brown fat engages fatty acid synthesis through AKT2 stimulated ChREBP activity, simultaneously with fatty acid oxidation, to maintain fuel storage
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE96681 | GEO | 2017/11/09
SECONDARY ACCESSION(S): PRJNA379360
REPOSITORIES: GEO
Similar Datasets
Project description:Active brown fat engages fatty acid synthesis through AKT2 stimulated ChREBP activity, simultaneously with fatty acid oxidation, to maintain fuel storage
| PRJNA379360 | ENA
Project description:Brown adipose tissue (BAT) is a therapeutic target for metabolic diseases; thus, understanding its metabolic circuitry is clinically important. Many studies of BAT compare rodents mildly cold to those severely cold. Here, we compared BAT remodeling between thermoneutral and mild-cold-adapted mice, conditions more relevant to humans. Although BAT is renowned for catabolic ?-oxidative capacity, we find paradoxically that the anabolic de novo lipogenesis (DNL) genes encoding ACLY, ACSS2, ACC, and FASN were among the most upregulated by mild cold and that, in humans, DNL correlates with Ucp1 expression. The regulation and function of adipocyte DNL and its association with thermogenesis are not understood. We provide evidence suggesting that AKT2 drives DNL in adipocytes by stimulating ChREBP? transcriptional activity and that cold induces the AKT2-ChREBP pathway in BAT to optimize fuel storage and thermogenesis. These data provide insight into adipocyte DNL regulation and function and illustrate the metabolic flexibility of thermogenesis.
| S-EPMC5762420 | biostudies-literature
Project description:A growing body of evidence indicates that peroxisome proliferator-activated receptor alpha (PPARalpha) not merely serves as a transcriptional regulator of fatty acid catabolism but also exerts a much broader role in hepatic lipid metabolism. We determined adaptations in hepatic lipid metabolism and related aspects of carbohydrate metabolism upon treatment of C57Bl/6 mice with the PPARalpha agonist fenofibrate. Stable isotope procedures were applied to assess hepatic fatty acid synthesis, fatty acid elongation, and carbohydrate metabolism. Fenofibrate treatment strongly induced hepatic de novo lipogenesis and chain elongation (+/-300, 150, and 600% for C16:0, C18:0, and C18:1 synthesis, respectively) in parallel with an increased expression of lipogenic genes. The lipogenic induction in fenofibrate-treated mice was found to depend on sterol regulatory element-binding protein 1c (SREBP-1c) but not carbohydrate response element-binding protein (ChREBP). Fenofibrate treatment resulted in a reduced contribution of glycolysis to acetyl-CoA production, whereas the cycling of glucose 6-phosphate through the pentose phosphate pathway presumably was enhanced. Altogether, our data indicate that beta-oxidation and lipogenesis are induced simultaneously upon fenofibrate treatment. These observations may reflect a physiological mechanism by which PPARalpha and SREBP-1c collectively ensure proper handling of fatty acids to protect the liver against cytotoxic damage.
| S-EPMC2797174 | biostudies-other
Project description:It has been found that fat oxidation is reduced in the skeletal muscle of obese humans. This study aims to identify the mRNA of proteins involved in fat oxidation that may be reduced in obese and morbidly obese individuals. Information gathered will help in understanding how obesity contributes to cardiovascular disease via insulin resistance. Keywords: other
2003-07-16 | GSE474 | GEO
Project description:OBJECTIVE:To determine the role of fatty acid oxidation on the cellular, molecular, and physiologic response of brown adipose tissue to disparate paradigms of chronic thermogenic stimulation. METHODS:Mice with an adipose-specific loss of Carnitine Palmitoyltransferase 2 (Cpt2A-/-), that lack mitochondrial long chain fatty acid ?-oxidation, were subjected to environmental and pharmacologic interventions known to promote thermogenic programming in adipose tissue. RESULTS:Chronic administration of ?3-adrenergic (CL-316243) or thyroid hormone (GC-1) agonists induced a loss of BAT morphology and UCP1 expression in Cpt2A-/- mice. Fatty acid oxidation was also required for the browning of white adipose tissue (WAT) and the induction of UCP1 in WAT. In contrast, chronic cold (15 °C) stimulation induced UCP1 and thermogenic programming in both control and Cpt2A-/- adipose tissue albeit to a lesser extent in Cpt2A-/- mice. However, thermoneutral housing also induced the loss of UCP1 and BAT morphology in Cpt2A-/- mice. Therefore, adipose fatty acid oxidation is required for both the acute agonist-induced activation of BAT and the maintenance of quiescent BAT. Consistent with this data, Cpt2A-/- BAT exhibited increased macrophage infiltration, inflammation and fibrosis irrespective of BAT activation. Finally, obese Cpt2A-/- mice housed at thermoneutrality exhibited a loss of interscapular BAT and were refractory to ?3-adrenergic-induced energy expenditure and weight loss. CONCLUSION:Mitochondrial long chain fatty acid ?-oxidation is critical for the maintenance of the brown adipocyte phenotype both during times of activation and quiescence.
| S-EPMC5784326 | biostudies-literature
Project description:Lipid storage droplet protein 5 (LSDP5) is a lipid droplet-associated protein of the PAT (perilipin, adipophilin, and TIP47) family that is expressed in the liver in a peroxisome proliferator-activated receptor alpha (PPAR?)-dependent manner; however, its exact function has not been elucidated. We noticed that LSDP5 was localized to the surface of lipid droplets in hepatocytes. Overexpression of LSDP5 enhanced lipid accumulation in the hepatic cell line AML12 and in primary hepatocytes. Knock-down of LSDP5 significantly decreased the triglyceride content of lipid droplets, stimulated lipolysis, and modestly increased the mitochondrial content and level of fatty-acid ?-oxidation in the mitochondria. The expression of PPAR? was increased in LSDP5-deficient cells and required for the increase in the level of fatty acid ?-oxidation in LSDP5-deficient cells. Using serial deletions of LSDP5, we determined that the lipid droplet-targeting domain and the domain directing lipid droplet clustering overlapped and were localized to the 188 amino acid residues at the N-terminus of LSDP5. Our findings suggest that LSDP5, a novel lipid droplet protein, may contribute to triglyceride accumulation by negatively regulating lipolysis and fatty acid oxidation in hepatocytes.
| S-EPMC3365886 | biostudies-literature
Project description:Brown adipose tissue uptake of glucose and fatty acids is very high during nonshivering thermogenesis. Adrenergic stimulation markedly increases glucose uptake, de novo lipogenesis, and FA oxidation simultaneously. The mechanism that enables this concerted response has hitherto been unknown. Here, we find that in primary brown adipocytes and brown adipocyte-derived cell line (IMBAT-1), acute inhibition and longer-term knockdown of DGAT2 links the increased de novo synthesis of fatty acids from glucose to a pool of TAG that is simultaneously hydrolyzed, providing FA for mitochondrial oxidation. DGAT1 does not contribute to this pathway, but uses exogenous FA and glycerol to synthesize a functionally distinct pool of TAG to which DGAT2 also contributes. The DGAT2-dependent channelling of 14C from glucose into TAG and CO2 was reproduced in ?3-agonist-stimulated primary brown adipocytes. Knockdown of DGAT2 in IMBAT-1 affected the mRNA levels of UCP1 and genes important in FA activation and esterification. Therefore, in ?3-agonist activated brown adipocytes, DGAT2 specifically enables channelling of de novo synthesized FA into a rapidly mobilized pool of TAG, which is simultaneously hydrolyzed to provide substrates for mitochondrial fatty acid oxidation.
| S-EPMC5234708 | biostudies-other
Project description:Metabolic impairments associated with obstructive sleep apnea syndrome (OSA) are linked to tissue hypoxia, however, the explanatory molecular and endocrine mechanisms remain unknown. Using gas-permeable cultureware, we studied the chronic effects of mild and severe hypoxia on free fatty acid (FFA) uptake, storage, and oxidation in L6 myotubes under 20, 4, or 1% O2. Additionally, the impact of metformin and the peroxisome proliferator-activated receptor (PPAR) ?/? agonist, called GW501516, were investigated. Exposure to mild and severe hypoxia reduced FFA uptake by 37 and 32%, respectively, while metformin treatment increased FFA uptake by 39% under mild hypoxia. GW501516 reduced FFA uptake under all conditions. Protein expressions of CD36 (cluster of differentiation 36) and SCL27A4 (solute carrier family 27 fatty acid transporter, member 4) were reduced by 17 and 23% under severe hypoxia. Gene expression of UCP2 (uncoupling protein 2) was reduced by severe hypoxia by 81%. Metformin increased CD36 protein levels by 28% under control conditions and SCL27A4 levels by 56% under mild hypoxia. Intracellular lipids were reduced by mild hypoxia by 18%, while in controls only, metformin administration further reduced intracellular lipids (20% O2) by 36%. Finally, palmitate oxidation was reduced by severe hypoxia, while metformin treatment reduced non-mitochondrial O2 consumption, palmitate oxidation, and proton leak at all O2 levels. Hypoxia directly reduced FFA uptake and intracellular lipids uptake in myotubes, at least partially, due to the reduction in CD36 transporters. Metformin, but not GW501516, can increase FFA uptake and SCL27A4 expression under mild hypoxia. Described effects might contribute to elevated plasma FFA levels and metabolic derangements in OSA.
| S-EPMC6199370 | biostudies-literature
Project description:Autophagy plays an important role in lipid breakdown, mitochondrial turnover, and mitochondrial function during brown adipose tissue (BAT) activation by thyroid hormone, but its role in BAT during adaptive thermogenesis remains controversial. Here, we examined BAT from mice exposed to 72 h of cold challenge as well as primary brown adipocytes treated with norepinephrine and found increased autophagy as well as increased β-oxidation, mitophagy, mitochondrial turnover, and mitochondrial activity. To further understand the role of autophagy of BAT in vivo, we generated BAT-specific Atg5 knockout (Atg5cKO) mice and exposed them to cold for 72 h. Interestingly, BAT-specific Atg5cKO mice were unable to maintain body temperature after chronic cold exposure and displayed deranged mitochondrial morphology and reactive oxygen species damage in their BAT. Our findings demonstrate the critical role of autophagy in adaptive thermogenesis, fatty acid metabolism, and mitochondrial function in BAT during chronic cold exposure.
| S-EPMC8134067 | biostudies-literature
Project description:Lymphatic vessels are involved in fluid drainage and are critical for health. To date, only genetic signaling pathways have been implicated in lymphatic development, and a role for metabolism has not been described. Here, we report that transcription factor Prox1 increases fatty acid ß-oxidation (FAO) through upregulation of CPT1a, a rate-controlling step of FAO. Lymphatic endothelial cells (LECs) oxidize fatty acids to proliferate and migrate. By providing acetyl-CoA, FAO is also critical for the maintenance of differentiated LECs through the regulation of histone acetylation of key lymphangiogenic genes. Loss of CPT1a in LEC precursors causes lymphatic defects in vivo, while restoration of acetyl-CoA by supplementing acetate to replenish cellular acetyl-CoA levels rescues this process.
2017-02-13 | GSE71230 | GEO