Evolution of brown fat: its absence in marsupials and monotremes

1992 ◽  
Vol 70 (1) ◽  
pp. 171-179 ◽  
Author(s):  
John S. Hayward ◽  
Paul A. Lisson

Species from all extant families of marsupials and monotremes were examined to clarify whether these mammalian subclasses possess brown adipose tissue. To optimize the chance of finding this tissue, special emphasis was given to sampling species adapted to colder regions, species with small adult body size, and individuals at a stage of development equivalent to the newborn stage of placentals (late pouch life in the case of marsupials). Evidence based on gross morphology and light, electron, and fluorescence microscopy failed to show the presence of brown adipose tissue in any marsupial or monotreme. All adipose tissue was typical white fat, including special instances where multilocularity of lipid droplets occurred in association with white adipocyte development or with fat mobilization resulting from nutritional or cold stress. These results, combined with lack of positive identification of brown adipose tissue in birds or other vertebrates, indicate that brown adipose tissue is unique to eutherian (placental) mammals and probably evolved early in the radiation of this subclass. This uniqueness presents the opportunity to suggest a more satisfactory name for the subclass: Thermolipia (from the Greek for "warm fat") or, commonly, thermolipials.

1985 ◽  
Vol 248 (1) ◽  
pp. E20-E25 ◽  
Author(s):  
M. Saito ◽  
Y. Minokoshi ◽  
T. Shimazu

The interscapular brown adipose tissue (IBAT) from obese rats with lesions of the ventromedial hypothalamus (VMH) was approximately 5 times heavier than those from controls. This hypertrophy of IBAT was associated with a marked enlargement of constituent adipocytes and their apparent transformation from multiloculated structure of lipid droplets into the uniloculated structure. The rate of fatty acid synthesis in IBAT of the obese rats was less than one-tenth of that in control rats and approximated the value in white adipose tissue (WAT) when they were starved for 24 h. When rats were fed, the synthetic rate was increased, but the lipogenic response of IBAT in the obese rats was much greater than that in controls, the extent of the response being comparable to that of WAT. The IBAT temperature rose rapidly on electrical stimulation of the sympathetic nerves to the tissue in control rats, whereas the temperature response was reduced markedly in the obese rats. It was suggested that thermogenesis in BAT was impaired in obese rats with VMH lesions by decreasing triglyceride turnover in BAT, probably due to dysfunction of the sympathetic nervous system and a consequent transformation of BAT into WAT.


2017 ◽  
Vol 98 (2) ◽  
pp. 100-108 ◽  
Author(s):  
Leidyanne Ferreira Gonçalves ◽  
Thaissa Queiroz Machado ◽  
Camila Castro-Pinheiro ◽  
Nathalia Guimaraes de Souza ◽  
Karen Jesus Oliveira ◽  
...  

1994 ◽  
Vol 302 (3) ◽  
pp. 695-700 ◽  
Author(s):  
C Manchado ◽  
P Yubero ◽  
O Viñas ◽  
R Iglesias ◽  
F Villarroya ◽  
...  

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.


2021 ◽  
pp. 10-18
Author(s):  
Irina Chernukha ◽  
Liliya Fedulova ◽  
Elena Kotenkova

Introduction. Traditionally, mammalian adipose tissue is divided into white (white adipose tissue – WAT) and brown (brown adipose tissue – BAT). While the functions of WAT are well known as the triglyceride depot, the role of BAT in mammalian physiology has been under close investigation. The first description of the role of BAT in maintaining thermogenesis dates back to 1961. This article offers a review of structural and functional specificity of white, beige and brown adipose tissue. Results and discussion. The differences and descriptions of adipocytes and their impact on the maintenance of the main functions of the mammalian body are described in this manuscript. In particular, thermogenesis, stress response, obesity, type II diabetes. In addition to WAT and BAT, an intermediate form was also detected in the body – beige fat (BeAT or Brite). The opposite opinions regarding the presence of three types of adipose tissue in the human and animal bodies are presented. Studies on the identification of uncoupling proteins 1 and 3 and their role in the transformation of white fat into beige/brown are considered. Basically, the data on the factors of endogenous and exogenous nature on their formation are given on the example of the human body. Conclusion. With an abundance of publications on the keywords: “white, brown fat”, these studies, in the overwhelming majority, are devoted to the role of these fats in the formation of human thermogenesis, the assessment of the impact on obesity. Pigs have also been suggested to lack functional BAT, which is a major cause of neonatal death in the swine industry, therefore the focus on investigating role of different types of adipose tissue in pigs seems very promising in order to understand whether there is a compensating mechanism of thermogenesis.


Author(s):  
O. Kalmykova ◽  
M. Dzerzhynsky

The aim of our study was to determine morpho-functional state (area of nucleus, brown adipocytes and also area and number of lipid droplets in each cells, general optical density of tissue) of brown adipose tissue in rats with high-calorie (high fat) dietinduced obesity after melatonin administration in different time of the day (morning and evening). Melatonin was administered daily by gavage for 7 weeks in dose 30 mg/kg either 1 h after lights-on (ZT01) or 1 h before lights-off (ZT11) rats with high-calorie diet (HCD). Besides morphometric parameters as well were measured related visceral fat weight and related brown adipose tissue mass. Rats with HCD had huge changes in brown adipocytes morphology, which summarized in become resembles of classical white adipocytes: grown lipid droplets and cells area, but goes down lipid droplets number and optical density of brown adipose tissue. In general brown adipose tissue with above mentioned characteristic from HCD rats lose their ability to conduct strongly thermoproduction function. After melatonin used in rats with HCD arise leveling of pathological changes, which associated with consumption of HCD. Namely, in groups HCD ZT01 and HCD ZT11 we obtain decreased cells and lipid droplets area, increased lipid droplets number and optical density of brown adipose tissue, in relation to group HCD. Therese received changes has evidence about functionally active brown adipose tissue state, which can also dissipate of exceed energy (lipids – triacylglycerols) amount into whole organism during heat production for avoid to its storage in white adipose tissue and in outside adipose tissue. In addition, evening administration of melatonin (group HCD ZT11) demonstrate more activated state of brown adipose tissueand also related visceral weight gain less, than morning(group HCD ZT01). In conclusions, melatonin influence on morpho-functional state brown adipose tissue in rats with HCD, moreover evening administration can use for obesity therapy via its strong action on activate brown adipocytes.


Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 1984-P
Author(s):  
RENATA PEREIRA ALAMBERT ◽  
SATYA MURTHY TADINADA ◽  
E. DALE ABEL

Cells ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 201 ◽  
Author(s):  
Junyu Liu ◽  
Chuanhai Zhang ◽  
Boyang Zhang ◽  
Yao Sheng ◽  
Wentao Xu ◽  
...  

Brown adipose tissue (BAT) plays an essential role in maintaining body temperature and in treating obesity and diabetes. The adult BAT (aBAT) and neonatal BAT (neBAT) vary greatly in capacity, but the characteristics and differences between them on the molecular level, as well as the related features of BAT as it develops post-delivery, have not yet been fully determined. In this study, we examined the morphological features of aBAT and neBAT of mice by using hematoxylin-eosin (H&E) staining, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). We found that neBAT contains a smaller number and size of lipid droplets, as well as more abundant mitochondria, compared with aBAT. The dynamic morphological changes revealed that the number and size of lipid droplets increase, but the number of mitochondria gradually decrease during the post-delivery development, which consisted of some differences in RNA or protein expression levels, such as gradually decreased uncoupling protein 1 (UCP1) expression levels and mitochondrial genes, such as mitochondrial transcription factor A (Tfam). The adipocyte differentiation-related genes, such as transcription factor CCAAT enhancer-binding protein β (CEBPβ), were also continuously upregulated. Additionally, the different features of aBAT and neBAT were analyzed from the global transcription (RNA-Seq) level, which included messenger RNA (mRNA), microRNA, long non-coding RNA (lncRNA), circRNA, and DNA methylation, as well as proteins (proteomics). Differentially methylated region (DMR) analysis identified 383 hyper- and 503 hypo-methylated genes, as well as 1221 new circRNA in ne-BAT and 1991 new circRNA in a-BAT, with significantly higher expression of circRNA in aBAT compared with neBAT. Gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that mitochondrial activity, protein synthesis, and cell life activity levels were higher in neBAT, and pathways related to ribosomes, spliceosomes, and metabolism were significantly activated in neBAT compared to aBAT. Collectively, this study describes the dynamic changes occurring throughout post-delivery development from the morphological, molecular and omics perspectives. Our study provides information that may be utilized in improving BAT functional activity through gene regulation and/or epigenetic regulation.


2020 ◽  
Vol 117 (36) ◽  
pp. 22080-22089 ◽  
Author(s):  
Matthew C. Tillman ◽  
Norihiro Imai ◽  
Yue Li ◽  
Manoj Khadka ◽  
C. Denise Okafor ◽  
...  

Nonshivering thermogenesis occurs in brown adipose tissue to generate heat in response to cold ambient temperatures. Thioesterase superfamily member 1 (Them1) is transcriptionally up-regulated in brown adipose tissue upon exposure to the cold and suppresses thermogenesis in order to conserve energy reserves. It hydrolyzes long-chain fatty acyl-CoAs that are derived from lipid droplets, preventing their use as fuel for thermogenesis. In addition to its enzymatic domains, Them1 contains a C-terminal StAR-related lipid transfer (START) domain with unknown ligand or function. By complementary biophysical approaches, we show that the START domain binds to long-chain fatty acids, products of Them1’s enzymatic reaction, as well as lysophosphatidylcholine (LPC), lipids shown to activate thermogenesis in brown adipocytes. Certain fatty acids stabilize the START domain and allosterically enhance Them1 catalysis of acyl-CoA, whereas 18:1 LPC destabilizes and inhibits activity, which we verify in cell culture. Additionally, we demonstrate that the START domain functions to localize Them1 near lipid droplets. These findings define the role of the START domain as a lipid sensor that allosterically regulates Them1 activity and spatially localizes it in proximity to the lipid droplet.


2016 ◽  
Vol 36 (15) ◽  
pp. 2027-2038 ◽  
Author(s):  
Hongyi Zhou ◽  
Stephen M. Black ◽  
Tyler W. Benson ◽  
Neal L. Weintraub ◽  
Weiqin Chen

Brown adipose tissue (BAT) plays a unique role in regulating whole-body energy homeostasis by dissipating energy through thermogenic uncoupling. Berardinelli-Seip congenital lipodystrophy (BSCL) type 2 (BSCL2; also known as seipin) is a lipodystrophy-associated endoplasmic reticulum membrane protein essential for white adipocyte differentiation. Whether BSCL2 directly participates in brown adipocyte differentiation, development, and function, however, is unknown. We show that BSCL2 expression is increased during brown adipocyte differentiation. Its deletion does not impair the classic brown adipogenic program but rather induces premature activation of differentiating brown adipocytes through cyclic AMP (cAMP)/protein kinase A (PKA)-mediated lipolysis and fatty acid and glucose oxidation, as well as uncoupling. cAMP/PKA signaling is physiologically activated during neonatal BAT development in wild-type mice and greatly potentiated in mice with genetic deletion ofBscl2in brown progenitor cells, leading to reduced BAT mass and lipid content during neonatal brown fat formation. However, prolonged overactivation of cAMP/PKA signaling during BAT development ultimately causes apoptosis of brown adipocytes through inflammation, resulting in BAT atrophy and increased overall adiposity in adult mice. These findings reveal a key cell-autonomous role for BSCL2 in controlling BAT mass/activity and provide novel insights into therapeutic strategies targeting cAMP/PKA signaling to regulate brown adipocyte function, viability, and metabolic homeostasis.


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