scholarly journals Iron chelation increases beige fat differentiation and metabolic activity, preventing and treating obesity

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Mojgan Nazari ◽  
Kenneth W. Ho ◽  
Natasha Langley ◽  
Kuan M. Cha ◽  
Raymond Kodsi ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Energy Expenditure ◽  
Uncoupling Protein ◽  
Iron Chelation ◽  
Iron Chelator ◽  
Brown Fat ◽  
Obesity And Diabetes ◽  
Brown Adipose ◽  
Total Daily Energy Expenditure ◽  
Beige Fat

AbstractBeige and brown fat consume glucose and lipids to produce heat, using uncoupling protein 1 (UCP1). It is thought that full activation of brown adipose tissue (BAT) may increase total daily energy expenditure by 20%. Humans normally have more beige and potentially beige-able fat than brown fat. Strategies to increase beige fat differentiation and activation may be useful for the treatment of obesity and diabetes. Mice were fed chow or high-fat diet (HFD) with or without the iron chelator deferasirox. Animals fed HFD + deferasirox were markedly lighter than their HFD controls with increased energy expenditure (12% increase over 24 h, p < 0.001). Inguinal fat from HFD + deferasirox mice showed increased beige fat quantity with greater Ucp1 and Prdm16 expression. Inguinal adipose tissue explants were studied in a Seahorse bioanalyser and energy expenditure was significantly increased. Deferasirox was also effective in established obesity and in ob/ob mice, indicating that intact leptin signalling is not needed for efficacy. These studies identify iron chelation as a strategy to preferentially activate beige fat. Whether activating brown/beige fat is effective in humans is unproven. However, depleting iron to low-normal levels is a potential therapeutic strategy to improve obesity and related metabolic disorders, and human studies may be warranted.

scholarly journals Protein kinase A induces UCP1 expression in specific adipose depots to increase energy expenditure and improve metabolic health

2016 ◽  
Vol 311 (1) ◽  
pp. R79-R88 ◽  
Author(s):  
Lorna M. Dickson ◽  
Shriya Gandhi ◽  
Brian T. Layden ◽  
Ronald N. Cohen ◽  
Barton Wicksteed
Keyword(s):  
Adipose Tissue ◽  
Energy Expenditure ◽  
Cell Function ◽  
Uncoupling Protein ◽  
Metabolic Health ◽  
Regulatory Subunit ◽  
Increase Energy Expenditure ◽  
Brown Adipose ◽  
Β Cell Function ◽  
Pka Regulatory Subunit

Adipose tissue PKA has roles in adipogenesis, lipolysis, and mitochondrial function. PKA transduces the cAMP signal downstream of G protein-coupled receptors, which are being explored for therapeutic manipulation to reduce obesity and improve metabolic health. This study aimed to determine the overall physiological consequences of PKA activation in adipose tissue. Mice expressing an activated PKA catalytic subunit in adipose tissue (Adipoq-caPKA mice) showed increased PKA activity in subcutaneous, epididymal, and mesenteric white adipose tissue (WAT) depots and brown adipose tissue (BAT) compared with controls. Adipoq-caPKA mice weaned onto a high-fat diet (HFD) or switched to the HFD at 26 wk of age were protected from diet-induced weight gain. Metabolic health was improved, with enhanced insulin sensitivity, glucose tolerance, and β-cell function. Adipose tissue health was improved, with smaller adipocyte size and reduced macrophage engulfment of adipocytes. Using metabolic cages, we found that Adipoq-caPKA mice were shown to have increased energy expenditure, but no difference to littermate controls in physical activity or food consumption. Immunoblotting of adipose tissue showed increased expression of uncoupling protein-1 (UCP1) in BAT and dramatic UCP1 induction in subcutaneous WAT, but no induction in the visceral depots. Feeding a HFD increased PKA activity in epididymal WAT of wild-type mice compared with chow, but did not change PKA activity in subcutaneous WAT or BAT. This was associated with changes in PKA regulatory subunit expression. This study shows that adipose tissue PKA activity is sufficient to increase energy expenditure and indicates that PKA is a beneficial target in metabolic health.

scholarly journals Iodothyronine 5′-deiodinase activity as an early event of prenatal brown-fat differentiation in bovine development

1989 ◽  
Vol 259 (2) ◽  
pp. 555-559 ◽  
Author(s):  
M Giralt ◽  
L Casteilla ◽  
O Viñas ◽  
T Mampel ◽  
R Iglesias ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Uncoupling Protein ◽  
Brown Fat ◽  
Early Event ◽  
Type I ◽  
Fetal Life ◽  
Reverse T3 ◽  
Deiodinase Activity ◽  
Brown Adipose

Iodothyronine 5'-deiodinase activity appears to be a type I enzyme in bovine brown adipose tissue, on the basis of its high Km for 3,3',5'-tri-iodothyronine (‘reverse T3’) (in the micromolar range) and sensitivity to propylthiouracil inhibition. This enzyme activity is already detectable in perirenal adipose tissue of bovine fetuses in the second month of gestation, reaches peak values around the seventh month of fetal life, declines before birth, becomes lower after parturition and finally undetectable in the adult cow. Iodothyronine 5'-deiodinase activity is present in the pericardic, peritoneal and intermuscular adipose depots of the neonatal calf, but it is always undetectable in the subcutaneous adipose tissue. It is concluded that iodothyronine 5'-deiodinase is a specific feature of brown fat in the bovine species that is not shared by white adipose tissue. white adipose tissue. Peak values of 5'-deiodinating activity appear as an early event in the prenatal differentiation programme of bovine brown-fat cells as they occur when uncoupling-protein-gene expression first starts.

scholarly journals Recent advances in our understanding of brown and beige adipose tissue: the good fat that keeps you healthy

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1129 ◽  
Author(s):  
Michael E. Symonds ◽  
Peter Aldiss ◽  
Mark Pope ◽  
Helen Budge
Keyword(s):  
Adipose Tissue ◽  
Thermal Environment ◽  
Uncoupling Protein ◽  
White Adipocytes ◽  
Brown Adipose ◽  
Adult Humans ◽  
Beige Fat ◽  
Rapid Generation ◽  
Beige Adipose Tissue ◽  
Shivering Thermogenesis

Brown adipose tissue (BAT) possesses a unique uncoupling protein (UCP1) which, when activated, enables the rapid generation of heat and the oxidation of lipids or glucose or both. It is present in small amounts (~15–350 mL) in adult humans. UCP1 is rapidly activated at birth and is essential in preventing hypothermia in newborns, who rapidly generate large amounts of heat through non-shivering thermogenesis. Since the “re-discovery” of BAT in adult humans about 10 years ago, there has been an exceptional amount of research interest. This has been accompanied by the establishment of beige fat, characterised as discrete areas of UCP1-containing cells dispersed within white adipocytes. Typically, the amount of UCP1 in these depots is around 10% of the amount found in classic BAT. The abundance of brown/beige fat is reduced with obesity, and the challenge is to prevent its loss with ageing or to reactivate existing depots or both. This is difficult, as the current gold standard for assessing BAT function in humans measures radio-labelled glucose uptake in the fasted state and is usually dependent on cold exposure and the same subject can be found to exhibit both positive and negative scans with repeated scanning. Rodent studies have identified multiple pathways that may modulate brown/beige fat function, but their direct relevance to humans is constrained, as these studies typically are undertaken in cool-adapted animals. BAT remains a challenging organ to study in humans and is able to swiftly adapt to changes in the thermal environment and thus enable rapid changes in heat production and glucose oxidation.

scholarly journals Liver X receptor β controls thyroid hormone feedback in the brain and regulates browning of subcutaneous white adipose tissue

2015 ◽  
Vol 112 (45) ◽  
pp. 14006-14011 ◽  
Author(s):  
Yifei Miao ◽  
Wanfu Wu ◽  
Yubing Dai ◽  
Laure Maneix ◽  
Bo Huang ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Thyroid Hormone ◽  
Energy Expenditure ◽  
White Adipose Tissue ◽  
Uncoupling Protein ◽  
Thyroid Stimulating Hormone ◽  
Vital Role ◽  
Normal Diet ◽  
Subcutaneous White Adipose Tissue ◽  
Brown Adipose

The recent discovery of browning of white adipose tissue (WAT) has raised great research interest because of its significant potential in counteracting obesity and type 2 diabetes. Browning is the result of the induction in WAT of a newly discovered type of adipocyte, the beige cell. When mice are exposed to cold or several kinds of hormones or treatments with chemicals, specific depots of WAT undergo a browning process, characterized by highly activated mitochondria and increased heat production and energy expenditure. However, the mechanisms underlying browning are still poorly understood. Liver X receptors (LXRs) are one class of nuclear receptors, which play a vital role in regulating cholesterol, triglyceride, and glucose metabolism. Following our previous finding that LXRs serve as repressors of uncoupling protein-1 (UCP1) in classic brown adipose tissue in female mice, we found that LXRs, especially LXRβ, also repress the browning process of subcutaneous adipose tissue (SAT) in male rodents fed a normal diet. Depletion of LXRs activated thyroid-stimulating hormone (TSH)-releasing hormone (TRH)-positive neurons in the paraventricular nucleus area of the hypothalamus and thus stimulated secretion of TSH from the pituitary. Consequently, production of thyroid hormones in the thyroid gland and circulating thyroid hormone level were increased. Moreover, the activity of thyroid signaling in SAT was markedly increased. Together, our findings have uncovered the basis of increased energy expenditure in male LXR knockout mice and provided support for targeting LXRs in treatment of obesity.

scholarly journals Possible involvement of uncoupling protein 1 in appetite control by leptin

2011 ◽  
Vol 236 (11) ◽  
pp. 1274-1281 ◽  
Author(s):  
Yuko Okamatsu-Ogura ◽  
Junko Nio-Kobayashi ◽  
Toshihiko Iwanaga ◽  
Akira Terao ◽  
Kazuhiro Kimura ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Food Intake ◽  
Energy Expenditure ◽  
Single Injection ◽  
Uncoupling Protein ◽  
Day Treatment ◽  
Repeated Injection ◽  
Appetite Control ◽  
Brown Adipose ◽  
Anorexigenic Effect

Leptin reduces body fat by decreasing food intake and increasing energy expenditure. Uncoupling protein (UCP) 1, a key molecule for brown adipose tissue (BAT) thermogenesis, was reported to contribute to the stimulatory effect of leptin on energy expenditure. To clarify whether UCP1 is also involved in the anorexigenic effect of leptin, in this study we examined the effect of leptin on food intake using wild-type (WT) and UCP1-deficient (UCP1-KO) mice. Repeated injection of leptin decreased food intake more markedly in WT mice than in UCP1-KO mice, while a single injection of leptin showed similar effects in the two groups of mice. As chronic leptin stimulation induces UCP1 expression in BAT and ectopically in white adipose tissue (WAT), we mimicked the UCP1 induction by repeated injection of CL316,243 (CL), a highly specific β3-adrenoceptor agonist, and measured food intake in response to a single injection of leptin. Two-week treatment with CL enhanced the anorexigenic effect of leptin in WT mice, but not in UCP1-KO mice. Three-day treatment with CL in WT mice also enhanced the anorexigenic effect of leptin and leptin-induced phosphorylation of signal transducer and activator of transcription 3 (STAT3) in the arcuate nucleus of the hypothalamus, without any notable change in adiposity. These results indicate that UCP1 enhances leptin action at the hypothalamus level, suggesting UCP1 contributes to the control of energy balance not only through the regulation of energy expenditure but also through appetite control by modulating leptin action.

scholarly journals Current Progress in Adipose Tissue Biology: Implications in Obesity and Its Comorbidities

2020 ◽  
Vol 12 (2) ◽  
pp. 85-101
Author(s):  
Anna Meiliana ◽  
Nurrani Mustika Dewi ◽  
Andi Wijaya
Keyword(s):  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Uncoupling Protein ◽  
Common Factor ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Protein Levels ◽  
Brown Adipose ◽  
Key Factor ◽  
Beige Fat

BACKGROUND: Obesity has been decades become a highly interest study, accompanied by the realization that adipose tissue (AT) plays a major role in the regulation of metabolic function.CONTENT: In past few years, adipocytes classification, development, and differentiation has been significant changes. The white adipose tissue (WAT) can transform to a phenotype like brown adipose (BAT) type and function. Exercise and cold induction were the most common factor for fat browning; however batokines such as fibroblast growth factor (FGF)-21, interleukin (IL)-6, Slit homolog 2 protein (SLIT2)-C, and Meteorin-like protein (METRNL) perform a beneficial browning action by increasing peroxisome proliferator-activated receptor gamma coactivator (PGC)-1α protein levels, a key factor to stimulate mitochondrial biogenesis and uncoupling Protein 1 (UCP1) transcription, thus change the WAT phenotype into beige.SUMMARY: AT recently known as a complex organ, not only bearing a storage function but as well as the master regulator of energy balance and nutritional homeostasis; brown and beige fat express constitutively high levels of thermogenic genes and raise our expectation on new strategies for fighting obesity and metabolic disorders.KEYWORDS: obesity, white adipose tissue, brown adipose tissue, beige adipose tissue, inflammation, IR, metabolic disease

scholarly journals ACE2 Pathway Regulates Thermogenesis and Energy Metabolism

2021 ◽  
Author(s):  
Xi Cao ◽  
Tingting Shi ◽  
Chuanhai Zhang ◽  
Wanzhu Jin ◽  
Lini Song ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Energy Expenditure ◽  
Brown Adipose Tissue ◽  
Knockout Mice ◽  
Metabolic Disorders ◽  
Energy Homeostasis ◽  
Cold Stimulation ◽  
Obesity And Diabetes ◽  
Brown Adipose ◽  
Pka Pathway

Identification of key regulators of energy homeostasis holds important therapeutic promise for metabolic disorders, such as obesity and diabetes. ACE2 cleaves angiotensin II (Ang II) to generate Ang-(1-7) which acts mainly through the Mas receptor. Here, we identify ACE2 pathway as a critical regulator in the maintenance of thermogenesis and energy expenditure. We found that ACE2 is highly expressed in brown adipose tissue (BAT) and that cold stimulation increases ACE2 and Ang-(1-7) levels in BAT and serum. ACE2 knockout mice (ACE2-/y), Mas knockout mice (Mas-/-), and the mice transplanted with brown adipose tissue from Mas-/- mice displayed impaired thermogenesis. In contrast, impaired thermogenesis of db/db obese diabetic mice and high-fat diet-induced obese mice were ameliorated by overexpression of ACE2 or continuous infusion of Ang-(1-7). Activation of ACE2 pathway was associated with improvement of metabolic parameters, including blood glucose, lipids and energy expenditure in multiple animal models. Consistently, ACE2 pathway remarkably enhanced the browning of white adipose tissue. Mechanistically, we showed that ACE2 pathway activated Akt/FoxO1 and PKA pathway, leading to induction of UCP1 and activation of mitochondrial function. Our data propose that adaptive thermogenesis requires regulation of ACE2 pathway and highlight novel therapeutic targets for the treatment of metabolic disorders.

scholarly journals Multifaceted Roles of Beige Fat in Energy Homeostasis Beyond UCP1

Endocrinology ◽  
2018 ◽  
Vol 159 (7) ◽  
pp. 2545-2553 ◽  
Author(s):  
Carlos Henrique Sponton ◽  
Shingo Kajimura
Keyword(s):  
Adipose Tissue ◽  
Energy Homeostasis ◽  
Uncoupling Protein ◽  
Developmental Regulation ◽  
Brown Adipocytes ◽  
Adipose Tissue Depots ◽  
Brown Adipose ◽  
Beige Adipocytes ◽  
Beige Fat ◽  
Adipose Cells

Abstract Beige adipocytes are an inducible form of thermogenic adipose cells that emerge within the white adipose tissue in response to a variety of environmental stimuli, such as chronic cold acclimation. Similar to brown adipocytes that reside in brown adipose tissue depots, beige adipocytes are also thermogenic; however, beige adipocytes possess unique, distinguishing characteristics in their developmental regulation and biological function. This review highlights recent advances in our understanding of beige adipocytes, focusing on the diverse roles of beige fat in the regulation of energy homeostasis that are independent of the canonical thermogenic pathway via uncoupling protein 1.

scholarly journals Chrysanthemum Leaf Ethanol Extract Prevents Obesity and Metabolic Disease in Diet-Induced Obese Mice via Lipid Mobilization in White Adipose Tissue

Nutrients ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1347 ◽  
Author(s):  
Ri Ryu ◽  
Eun-Young Kwon ◽  
Ji-Young Choi ◽  
Jong Cheol Shon ◽  
Kwang-Hyeon Liu ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Energy Expenditure ◽  
White Adipose Tissue ◽  
Ethanol Extract ◽  
The Body ◽  
Obese Mice ◽  
Peripheral Tissues ◽  
Lipid Mobilization ◽  
Obesity And Diabetes ◽  
Brown Adipose

This study aimed to elucidate the molecular mechanism of Chrysanthemum morifolium Ramat. against obesity and diabetes, by comparing the transcriptional changes in epididymal white adipose tissue (eWAT) with those of the bioactive compound in C. morifolium, luteolin (LU). Male C57BL/6J mice were fed a normal diet, high-fat diet (HFD), and HFD supplemented with 1.5% w/w chrysanthemum leaf ethanol extract (CLE) for 16 weeks. Supplementation with CLE and LU significantly decreased the body weight gain and eWAT weight by stimulating mRNA expressions for thermogenesis and energy expenditure in eWAT via lipid mobilization, which may be linked to the attenuation of dyslipidemia. Furthermore, CLE and LU increased uncoupling protein-1 protein expression in brown adipose tissue, leading to energy expenditure. Of note, CLE and LU supplements enhanced the balance between lipid storage and mobilization in white adipose tissue (WAT), in turn, inhibiting adipocyte inflammation and lipotoxicity of peripheral tissues. Moreover, CLE and LU attenuated hepatic steatosis by suppressing hepatic lipogenesis, thereby ameliorating insulin resistance and dyslipidemia. Our data suggest that CLE helps inhibit obesity and its comorbidities via the complex interplay between liver and WAT in diet-induced obese mice.

scholarly journals CCAAT/enhancer-binding proteins α and β in brown adipose tissue: evidence for a tissue-specific pattern of expression during development

1994 ◽  
Vol 302 (3) ◽  
pp. 695-700 ◽  
Author(s):  
C Manchado ◽  
P Yubero ◽  
O Viñas ◽  
R Iglesias ◽  
F Villarroya ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Uncoupling Protein ◽  
Brown Fat ◽  
Brown Adipocyte ◽  
Fetal Life ◽  
Inhibitory Protein ◽  
Adult Rats ◽  
Stage Of Development ◽  
Brown Adipose

CCAAT/enhancer-binding protein (C/EBP) alpha mRNA and its protein products C/EBP alpha and 30 kDa C/EBP alpha are expressed in rat brown-adipose tissue. Results also demonstrate the expression of C/EBP beta mRNA and its protein products C/EBP beta and liver inhibitory protein (LIP) in the tissue. The abundance of C/EBP alpha and C/EBP beta proteins in adult brown fat is similar to that found in adult liver. However, the expression of C/EBP alpha and C/EBP beta is specifically regulated in brown fat during development. C/EBP alpha, 30 kDa C/EBP alpha, C/EBP beta and LIP content is several-fold higher in fetal brown fat than in the adult tissue, or liver at any stage of development. Peak values are attained in late fetal life, in concurrence with the onset of transcription of the uncoupling protein (UCP) gene, the molecular marker of terminal brown-adipocyte differentiation. When adult rats are exposed to a cold environment, which is a physiological stimulus of brown-adipose tissue hyperplasia and UCP gene expression, a specific rise in C/EBP beta expression with respect to C/EBP alpha, 30 kDa C/EBP alpha and LIP is observed. Present data suggest that the C/EBP family of transcription factors has an important role in the development and terminal differentiation of brown-adipose tissue.

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