scholarly journals NAD+-dependent deacetylase SIRT3 in adipocytes is dispensable for maintaining normal adipose tissue mitochondrial function and whole body metabolism

2018 ◽  
Vol 315 (4) ◽  
pp. E520-E530 ◽  
Author(s):  
Lane C. Porter ◽  
Michael P. Franczyk ◽  
Terri Pietka ◽  
Shintaro Yamaguchi ◽  
Jonathan B. Lin ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Lipid Metabolism ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Whole Body ◽  
Metabolic Complications ◽  
Glucose And Lipid Metabolism ◽  
Brown Adipose ◽  
Gene And Protein Expression ◽  
Whole Body Metabolism

Mitochondrial dysfunction in adipose tissue is involved in the pathophysiology of obesity-induced systemic metabolic complications, such as type 2 diabetes, insulin resistance, and dyslipidemia. However, the mechanisms responsible for obesity-induced adipose tissue mitochondrial dysfunction are not clear. The aim of present study was to test the hypothesis that nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase sirtuin-3 (SIRT3) in adipocytes plays a critical role in adipose tissue mitochondrial biology and obesity. We first measured adipose tissue SIRT3 expression in obese and lean mice. Next, adipocyte-specific mitochondrial Sirt3 knockout (AMiSKO) mice were generated and metabolically characterized. We evaluated glucose and lipid metabolism in adult mice fed either a regular-chow diet or high-fat diet (HFD) and in aged mice. We also determined the effects of Sirt3 deletion on adipose tissue metabolism and mitochondrial biology. Supporting our hypothesis, obese mice had decreased SIRT3 gene and protein expression in adipose tissue. However, despite successful knockout of SIRT3, AMiSKO mice had normal glucose and lipid metabolism and did not change metabolic responses to HFD-feeding and aging. In addition, loss of SIRT3 had no major impact on putative SIRT3 targets, key metabolic pathways, and mitochondrial function in white and brown adipose tissue. Collectively, these findings suggest that adipocyte SIRT3 is dispensable for maintaining normal adipose tissue mitochondrial function and whole body metabolism. Contrary to our hypothesis, loss of SIRT3 function in adipocytes is unlikely to contribute to the pathophysiology of obesity-induced metabolic complications.

scholarly journals Multiple effects of cold exposure on livers of male mice

2018 ◽  
Vol 238 (2) ◽  
pp. 91-106 ◽  
Author(s):  
Aldo Grefhorst ◽  
Johanna C van den Beukel ◽  
Wieneke Dijk ◽  
Jacobie Steenbergen ◽  
Gardi J Voortman ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Lipid Metabolism ◽  
Cold Exposure ◽  
Ldl Receptor ◽  
Whole Body ◽  
Hepatic Lipid Metabolism ◽  
Hepatic Lipid ◽  
Hepatic Expression ◽  
Brown Adipose ◽  
Whole Body Metabolism

Cold exposure of mice is a common method to stimulate brown adipose tissue (BAT) activity and induce browning of white adipose tissue (WAT) that has beneficial effects on whole-body lipid metabolism, including reduced plasma triglyceride (TG) concentrations. The liver is a key regulatory organ in lipid metabolism as it can take up as well as oxidize fatty acids. The liver can also synthesize, store and secrete TGs in VLDL particles. The effects of cold exposure on murine hepatic lipid metabolism have not been addressed. Here, we report the effects of 24-h exposure to 4°C on parameters of hepatic lipid metabolism of male C57BL/6J mice. Cold exposure increased hepatic TG concentrations by 2-fold (P < 0.05) but reduced hepatic lipogenic gene expression. Hepatic expression of genes encoding proteins involved in cholesterol synthesis and uptake such as the LDL receptor (LDLR) was significantly increased upon cold exposure. Hepatic expression of Cyp7a1 encoding the rate-limiting enzyme in the classical bile acid (BA) synthesis pathway was increased by 4.3-fold (P < 0.05). Hepatic BA concentrations and fecal BA excretion were increased by 2.8- and 1.3-fold, respectively (P < 0.05 for both). VLDL-TG secretion was reduced by approximately 50% after 24 h of cold exposure (P < 0.05). In conclusion, cold exposure has various, likely intertwined effects on the liver that should be taken into account when studying the effects of cold exposure on whole-body metabolism.

Rapid changes in metabolic cold defense and GDP binding to brown adipose tissue mitochondria of rat pups

1993 ◽  
Vol 264 (5) ◽  
pp. R1017-R1023 ◽  
Author(s):  
G. Kortner ◽  
K. Schildhauer ◽  
O. Petrova ◽  
I. Schmidt
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Time Course ◽  
Developmental Changes ◽  
Whole Body ◽  
Rat Pups ◽  
Brown Adipose ◽  
Rapid Changes ◽  
Whole Body Metabolism

To determine developmental changes of brown adipose tissue (BAT) thermogenic activity at defined circadian and thermal states, we evaluated the time course of cold-induced increases of in vitro guanosine 5'-diphosphate (GDP) binding in parallel with whole body metabolism (oxygen consumption, VO2) and core temperature (Tc) in 1- to 11-day-old rat pups. During the maximum phase of the juvenile diurnal cycle, Tc of littermates was recorded continuously and VO2 alternately until 2 min before animals were killed for removal of interscapular BAT. GDP binding after 1.5 h at thermoneutrality and its increase during physiologically comparable cold loads were significantly lower in 1-day-old pups than in 5- and 11-day-old pups. Cold defense was activated more rapidly in the older pups, but GDP binding in even the 1-day-old pups was significantly increased during the second 10-min period of cold exposure. We conclude that rapid changes in thermogenic activity, in connection with the known developmental changes in the dependence of the suckling rat's metabolic cold defense on maternal and sibling contact and circadian phase, will distort longitudinal studies of any fast-changing BAT parameter when the conditions immediately before tissue removal are not thoroughly controlled.

scholarly journals Enhanced glycogen metabolism in adipose tissue decreases triglyceride mobilization

2010 ◽  
Vol 299 (1) ◽  
pp. E117-E125 ◽  
Author(s):  
Kathleen R. Markan ◽  
Michael J. Jurczak ◽  
Margaret B. Allison ◽  
Honggang Ye ◽  
Maria M. Sutanto ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Lipid Metabolism ◽  
Lactate Production ◽  
Transgenic Animals ◽  
Whole Body ◽  
Nonesterified Fatty Acids ◽  
Transgenic Mouse Line ◽  
Whole Body Metabolism

Adipose tissue is a primary site for lipid storage containing trace amounts of glycogen. However, refeeding after a prolonged partial fast produces a marked transient spike in adipose glycogen, which dissipates in coordination with the initiation of lipid resynthesis. To further study the potential interplay between glycogen and lipid metabolism in adipose tissue, the aP2-PTG transgenic mouse line was utilized since it contains a 100- to 400-fold elevation of adipocyte glycogen levels that are mobilized upon fasting. To determine the fate of the released glucose 1-phosphate, a series of metabolic measurements were made. Basal and isoproterenol-stimulated lactate production in vitro was significantly increased in adipose tissue from transgenic animals. In parallel, basal and isoproterenol-induced release of nonesterified fatty acids (NEFAs) was significantly reduced in transgenic adipose tissue vs. control. Interestingly, glycerol release was unchanged between the genotypes, suggesting that enhanced triglyceride resynthesis was occurring in the transgenic tissue. Qualitatively similar results for NEFA and glycerol levels between wild-type and transgenic animals were obtained in vivo during fasting. Additionally, the physiological upregulation of the phospho enolpyruvate carboxykinase cytosolic isoform (PEPCK-C) expression in adipose upon fasting was significantly blunted in transgenic mice. No changes in whole body metabolism were detected through indirect calorimetry. Yet weight loss following a weight gain/loss protocol was significantly impeded in the transgenic animals, indicating a further impairment in triglyceride mobilization. Cumulatively, these results support the notion that the adipocyte possesses a set point for glycogen, which is altered in response to nutritional cues, enabling the coordination of adipose glycogen turnover with lipid metabolism.

scholarly journals Chronic dietary supplementation of proanthocyanidins corrects the mitochondrial dysfunction of brown adipose tissue caused by diet-induced obesity in Wistar rats

2011 ◽  
Vol 107 (2) ◽  
pp. 170-178 ◽  
Author(s):  
David Pajuelo ◽  
Helena Quesada ◽  
Sabina Díaz ◽  
Anabel Fernández-Iglesias ◽  
Anna Arola-Arnal ◽  
...  
Keyword(s):  
Gene Expression ◽  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Citrate Synthase ◽  
Sirtuin 1 ◽  
Male Rats ◽  
Diet Induced Obesity ◽  
Brown Adipose

The present study aims to determine the effects of grape seed proanthocyanidin extract (GSPE) on brown adipose tissue (BAT) mitochondrial function in a state of obesity induced by diet. Wistar male rats were fed with a cafeteria diet (Cd) for 4 months; during the last 21 d, two groups were treated with doses of 25 and 50 mg GSPE/kg body weight. In the BAT, enzymatic activities of citrate synthase, cytochrome c oxidase (COX) and ATPase were determined and gene expression was analysed by real-time PCR. The mitochondrial function of BAT was determined in fresh mitochondria by high-resolution respirometry using both pyruvate and carnitine–palmitoyl-CoA as substrates. The results show that the Cd causes an important decrease in the gene expression of sirtuin 1, nuclear respiratory factor 1, isocitrate dehydrogenase 3γ and COX5α and, what is more telling, decreases the levels of mitochondrial respiration both with pyruvate and canitine–palmitoyl-CoA. Most of these parameters, which are indicative of mitochondrial dysfunction due to diet-induced obesity, are improved by chronic supplementation of GSPE. The beneficial effects caused by the administration of GSPE are exhibited as a protection against weight gain, in spite of the Cd the rats were fed. These data indicate that chronic consumption of a moderate dose of GSPE can correct an energy imbalance in a situation of diet-induced obesity, thereby improving the mitochondrial function and thermogenic capacity of the BAT.

scholarly journals The functional role of brown adipose tissue in whole‐body lipid metabolism in humans (1160.3)

2014 ◽  
Vol 28 (S1) ◽  
Author(s):  
Maria Chondronikola ◽  
Craig Porter ◽  
Nicholas Hurren ◽  
Tony Chao ◽  
Christina Yfanti ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Lipid Metabolism ◽  
Brown Adipose Tissue ◽  
Functional Role ◽  
Whole Body ◽  
Body Lipid ◽  
Brown Adipose

Autocrine effects of transgenic resistin on brown adipose tissue glucose and lipid metabolism

2017 ◽  
Vol 263 ◽  
pp. e71
Author(s):  
Jaroslava Trnovská ◽  
Michal Pravenec ◽  
Jan Silhavy ◽  
Hynek Strnad ◽  
Sebastian Eigner ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Lipid Metabolism ◽  
Brown Adipose Tissue ◽  
Glucose And Lipid Metabolism ◽  
Brown Adipose

Cyanidin-3-glucoside increases whole body energy metabolism by upregulating brown adipose tissue mitochondrial function

2017 ◽  
Vol 61 (11) ◽  
pp. 1700261 ◽  
Author(s):  
Yilin You ◽  
Xiaoxue Yuan ◽  
Xiaomeng Liu ◽  
Chen Liang ◽  
Minghui Meng ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Energy Metabolism ◽  
Brown Adipose Tissue ◽  
Mitochondrial Function ◽  
Whole Body ◽  
Brown Adipose ◽  
Body Energy
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