scholarly journals Breaking BAT: can browning create a better white?

2015 ◽  
Vol 228 (1) ◽  
pp. R19-R29 ◽  
Author(s):  
Amy Warner ◽  
Jens Mittag

Obesity and its comorbidities are a growing problem worldwide. In consequence, several new strategies have been proposed to promote weight loss and improve insulin sensitivity. Recently, it has been demonstrated that certain populations of white adipocytes can be ‘browned’, i.e., recruited to a more brown-like adipocyte, capable of thermogenesis through increased expression of uncoupling protein 1. The list of browning agents that induce these so-called beige adipocytes is growing constantly. However, the underlying mechanisms are often poorly understood, with the possibility that some of these agents cause browning as a secondary effect. Moreover, it remains unclear whether beige adipocytes can contribute sufficiently to affect whole-body energy expenditure in a functionally significant manner. This review presents an overview of the different molecular pathways leading to the induction of beige fat, including direct stimulation and indirect actions on the CNS or the immune system. We discuss the available evidence on the capacity of beige adipocytes to influence whole-body energy expenditure in rodents, and lastly outline the potential problems of translating browning capacity into the potential treatment of human metabolic diseases.

Author(s):  
Érique Castro ◽  
Tiago E. Oliveira Silva ◽  
William T. Festuccia

AbstractBeige (or brite, “brown in white”) adipocytes are uncoupling protein 1 (UCP1)-positive cells residing in white adipose depots that, depending on the conditions, behave either as classic white adipocytes, storing energy as lipids, or as brown adipocytes, dissipating energy from oxidative metabolism as heat through non-shivering thermogenesis. Because of their thermogenic potential and, therefore, possible usage to treat metabolic diseases such as obesity and type 2 diabetes, beige cells have attracted the attention of many scientists worldwide aiming to develop strategies to safely recruit and activate their thermogenic activity. Indeed, in recent years, a large variety of conditions, molecules (including nutrients) and signaling pathways were reported to promote the recruitment of beige adipocytes. Despite of those advances, the true contribution of beige adipocyte thermogenesis to whole-body energy expenditure is still not completely defined. Herein, we discuss some important aspects that should be considered when studying beige adipocyte biology and the contribution to energy balance and whole-body metabolism.


Antioxidants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1418
Author(s):  
Woo Yong Park ◽  
Gahee Song ◽  
Ja Yeon Park ◽  
Kwan-Il Kim ◽  
Kwang Seok Ahn ◽  
...  

The extract of the Gardenia jasminoides fruit (GJFE) can been consumed as an herbal tea or used as a yellow dye. Recently, studies report that GFJE exerts inhibitory effects on lipid accumulation and adipogenesis in white adipocytes. We evaluated the thermogenic actions of GJFE by focusing on mitochondrial activation and studying the underlying mechanisms. To investigate the role of GJFE on thermogenesis in mice, we used an acute cold exposure model. After 2 weeks of feeding, the cold tolerance of GJFE-fed mice was notably increased compared to PBS-fed mice. This was due to an increase in thermogenic proteins in the inguinal white adipose tissue of the cold-exposed mice. Moreover, GJFE significantly increased thermogenic factors such as peroxisome proliferator-activated receptor gamma (PPARγ), uncoupling protein 1 (UCP1), and PPARγ coactivator 1 alpha (PGC1α) in vitro as well. Factors related to mitochondrial abundance and functions were also induced by GJFE in white and beige adipocytes. However, the treatment of PPARγ inhibitor abolished the GJFE-induced changes, indicating that activation of PPARγ is critical for the thermogenic effect of GJFE. In conclusion, GJFE induces thermogenic action by activating mitochondrial function via PPARγ activation. Through these findings, we suggest GJFE as a potential anti-obesity agent with a novel mechanism involving thermogenic action in white adipocytes.


2016 ◽  
Vol 310 (8) ◽  
pp. E676-E687 ◽  
Author(s):  
Tomoya Sakamoto ◽  
Takahiro Nitta ◽  
Koji Maruno ◽  
Yu-Sheng Yeh ◽  
Hidetoshi Kuwata ◽  
...  

Emergence of thermogenic adipocytes such as brown and beige adipocytes is critical for whole body energy metabolism. Promoting the emergence of these adipocytes, which increase energy expenditure, could be a viable strategy in treating obesity and its related diseases. However, little is known regarding the mechanisms that regulate the emergence of these adipocytes in obese adipose tissue. Here, we demonstrated that classically activated macrophages (M1 Mϕ) suppress the induction of thermogenic adipocytes in obese adipose tissues of mice. Cold exposure significantly induced the expression levels of uncoupling protein-1 (UCP1), which is a mitochondrial protein unique in thermogenic adipocytes, in C57BL/6 mice fed a normal diet. However, UCP1 induction was significantly suppressed in adipose tissues of C57BL/6 mice fed a high-fat diet, into which M1 Mϕ infiltrated. Depletion of M1 Mϕ using clodronate liposomes eliminated the suppressive effect and markedly reduced the mRNA level of tumor necrosis factor-α (TNFα) in the adipose tissues. Importantly, consistent with the observed changes in the expression levels of marker genes for thermogenic adipocytes, combination treatment of clodronate liposome and cold exposure resulted in metabolic benefits such as lowered body weight and blood glucose level in obese mice. Moreover, intraperitoneal injection of recombinant TNFα protein suppressed UCP1 induction in lean adipose tissues of mice. Collectively, our data indicate that infiltrated M1 Mϕ suppress the induction of thermogenic adipocytes in obese adipose tissues via TNFα. This report suggests that inflammation induced by infiltrated Mϕ could cause not only insulin resistance but also reduction of energy expenditure in adipose tissues.


2019 ◽  
Vol 13 (1) ◽  
pp. 002
Author(s):  
Tahniyah Haq ◽  
Frank Joseph Ong ◽  
Sarah Kanji

Brown adipose tissue, a thermogenic organ, previously thought to be present in only small mammals and children has recently been identified in adult humans. Located primarily in the supraclavicular and cervical area, it produces heat by uncoupling oxidative phosphorylation due to the unique presence of uncoupling protein 1 by a process called nonshivering thermogenesis. BAT activity depends on many factors including age, sex, adiposity and outdoor temperature. Positron-emission tomography using 18F-fluorodeoxyglucose and computed tomography (18F-FDG PET–CT), magnetic resonance imaging (MRI) and thermal imaging (IRT) are among several methods used to detect BAT in humans. The importance of BAT is due to its role in whole body energy expenditure and fuel metabolism. Thus it is postulated that it may be useful in the treatment of metabolic diseases. However, there are still many unanswered questions to the clinical usefulness of this novel tissue. IMC J Med Sci 2019; 13(1): 002


2020 ◽  
Vol 134 (5) ◽  
pp. 473-512 ◽  
Author(s):  
Ryan P. Ceddia ◽  
Sheila Collins

Abstract With the ever-increasing burden of obesity and Type 2 diabetes, it is generally acknowledged that there remains a need for developing new therapeutics. One potential mechanism to combat obesity is to raise energy expenditure via increasing the amount of uncoupled respiration from the mitochondria-rich brown and beige adipocytes. With the recent appreciation of thermogenic adipocytes in humans, much effort is being made to elucidate the signaling pathways that regulate the browning of adipose tissue. In this review, we focus on the ligand–receptor signaling pathways that influence the cyclic nucleotides, cAMP and cGMP, in adipocytes. We chose to focus on G-protein–coupled receptor (GPCR), guanylyl cyclase and phosphodiesterase regulation of adipocytes because they are the targets of a large proportion of all currently available therapeutics. Furthermore, there is a large overlap in their signaling pathways, as signaling events that raise cAMP or cGMP generally increase adipocyte lipolysis and cause changes that are commonly referred to as browning: increasing mitochondrial biogenesis, uncoupling protein 1 (UCP1) expression and respiration.


2020 ◽  
Vol 245 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Zhe-Zhen Liao ◽  
Xiao-Yan Qi ◽  
Ya-Di Wang ◽  
Jiao-Yang Li ◽  
Qian-Qian Gu ◽  
...  

Remodeling of energy-storing white fat into energy-consuming beige fat has led to a promising new approach to alleviate adiposity. Several studies have shown adipokines can induce white adipose tissue (WAT) beiging through autocrine or paracrine actions. Betatrophin, a novel adipokine, has been linked to energy expenditure and lipolysis but not clearly clarified. Here, we using high-fat diet-induced obesity to determine how betatrophin modulate beiging and adiposity. We found that betatrophin-knockdown mice displayed less white fat mass and decreased plasma TG and NEFA levels. Consistently, inhibition of betatrophin leads to the phenotype change of adipocytes characterized by increased mitochondria contents, beige adipocytes and mitochondria biogenesis-specific markers both in vivo and in vitro. Of note, blocking AMP-activated protein kinase (AMPK) signaling pathway is able to abolish enhanced beige-like characteristics in betatrophin-knockdown adipocytes. Collectively, downregulation of betatrophin induces beiging in white adipocytes through activation of AMPK signaling pathway. These processes suggest betatrophin as a latent therapeutic target for obesity.


2017 ◽  
Vol 114 (20) ◽  
pp. 5265-5270 ◽  
Author(s):  
Delphine Duteil ◽  
Milica Tosic ◽  
Dominica Willmann ◽  
Anastasia Georgiadi ◽  
Toufike Kanouni ◽  
...  

Aging is accompanied by major changes in adipose tissue distribution and function. In particular, with time, thermogenic-competent beige adipocytes progressively gain a white adipocyte morphology. However, the mechanisms controlling the age-related transition of beige adipocytes to white adipocytes remain unclear. Lysine-specific demethylase 1 (Lsd1) is an epigenetic eraser enzyme positively regulating differentiation and function of adipocytes. Here we show that Lsd1 levels decrease in aging inguinal white adipose tissue concomitantly with beige fat cell decline. Accordingly, adipocyte-specific increase of Lsd1 expression is sufficient to rescue the age-related transition of beige adipocytes to white adipocytes in vivo, whereas loss of Lsd1 precipitates it. Lsd1 maintains beige adipocytes by controlling the expression of peroxisome proliferator-activated receptor α (Ppara), and treatment with a Ppara agonist is sufficient to rescue the loss of beige adipocytes caused by Lsd1 ablation. In summary, our data provide insights into the mechanism controlling the age-related beige-to-white adipocyte transition and identify Lsd1 as a regulator of beige fat cell maintenance.


2006 ◽  
Vol 25 (3) ◽  
pp. 489-496 ◽  
Author(s):  
Peter Junghans ◽  
Michael Derno ◽  
Stefan Pierzynowski ◽  
Ulf Hennig ◽  
Paul Eberhard Rudolph ◽  
...  

2020 ◽  
Vol 117 (5) ◽  
pp. 2462-2472 ◽  
Author(s):  
Keli Liu ◽  
Liangyu Lin ◽  
Qing Li ◽  
Yueqing Xue ◽  
Fanjun Zheng ◽  
...  

Preadipocytes can give rise to either white adipocytes or beige adipocytes. Owing to their distinct abilities in nutrient storage and energy expenditure, strategies that specifically promote “beiging” of adipocytes hold great promise for counterbalancing obesity and metabolic diseases. Yet, factors dictating the differentiation fate of adipocyte progenitors remain to be elucidated. We found that stearoyl-coenzyme A desaturase 1 (Scd1)-deficient mice, which resist metabolic stress, possess augmentation in beige adipocytes under basal conditions. Deletion of Scd1 in mature adipocytes expressing Fabp4 or Ucp1 did not affect thermogenesis in mice. Rather, Scd1 deficiency shifted the differentiation fate of preadipocytes from white adipogenesis to beige adipogenesis. Such effects are dependent on succinate accumulation in adipocyte progenitors, which fuels mitochondrial complex II activity. Suppression of mitochondrial complex II by Atpenin A5 or oxaloacetic acid reverted the differentiation potential of Scd1-deficient preadipocytes to white adipocytes. Furthermore, supplementation of succinate was found to increase beige adipocyte differentiation both in vitro and in vivo. Our data reveal an unappreciated role of Scd1 in determining the cell fate of adipocyte progenitors through succinate-dependent regulation of mitochondrial complex II.


2018 ◽  
Vol 43 (5) ◽  
pp. 528-530 ◽  
Author(s):  
Marc Teschler ◽  
Alfred Wassermann ◽  
Anja Weissenfels ◽  
Michael Fröhlich ◽  
Matthias Kohl ◽  
...  

To determine the underlying mechanisms after 1 session of (intense) whole-body electromyostimulation (WB-EMS) on total energy expenditure (TEE) and resting metabolic rate (RMR), 16 subjects followed a standardized protocol of indirect calorimetry for up to 72 h in 12-h intervals. The single session significantly increased RMR by approximately 25% ± 10% (p < 0.001) and TEE by approximately 9.5% ± 1%, a net effect of ∼460 ± 50 kcal (WB-EMS vs. control group).


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