scholarly journals Cold exposure induces different uncoupling-protein thermogenin masking/unmasking processes in brown adipose tissue depending on mitochondrial subtypes

1994 ◽  
Vol 300 (2) ◽  
pp. 463-468 ◽  
Author(s):  
M Moreno ◽  
P Puigserver ◽  
J Llull ◽  
M Gianotti ◽  
A Lanni ◽  
...  

The effect of cold exposure on thermogenic parameters such as mitochondrial protein content, GDP-binding and uncoupling protein (UCP) levels in different mitochondrial fractions from rat brown adipose tissue has been investigated. Rats were exposed from 12 h to 5 days at 4 degrees C, and three mitochondrial fractions were isolated by differential centrifugation: the M1 fraction (1000 g), the M3 fraction (3000 g) and the M15 fraction (15,000 g). Cytochrome c oxidase activity as an index of mitochondrial mass showed an increase during cold exposure. During the first 24 h of cold exposure UCP was incorporated specifically into the M3 and M15 mitochondrial fractions, and thereafter UCP appeared in the heaviest M1 fraction. However, specific GDP binding was increased during the first 24 h in the same way in all subpopulations, and this increase continued up to 72 h of cold exposure. Results suggest that different molecular events are involved during acute and chronic adaptation to cold: during the first 24 h of cold acclimatization, thermogenic activity is increased by an unmasking process of the UCP binding sites in the M1 mitochondrial fraction as UCP levels were constant and GDP binding increased, but in the M3 and M15 fraction the increase in thermogenic activity was completely due to an increase in GDP binding induced by a specific incorporation of UCP targeted to these mitochondria. Thus thermogenic parameters change in a different way in the brown-fat mitochondrial subpopulations during cold acclimatization.

1997 ◽  
Vol 77 (6) ◽  
pp. 871-883 ◽  
Author(s):  
Lynne Clarke ◽  
Michael J. Bryant ◽  
Michael A. Lomax ◽  
Michael E. Symonds

AbstractWe examined the effect of maternal chronic cold exposure, induced by winter-shearing ewes 4 weeks before their predicted lambing date, on brown adipose tissue (BAT) and liver development in lambs. Fetuses were sampled from under-fed (60% of energy requirements for maintenance and pregnancy of an unshorn ewe) shorn or unshorn ewes at 126,140 and 145 d of gestation. Lambs were sampled from ewes within 2 h of birth. Throughout gestation fetal body, BAT and liver weights were similar in shorn and unshorn groups. The level of GDP binding to mitochondrial uncoupling protein remained low throughout gestation, but increased dramatically after birth. Lambs born to shorn ewes possesd more mitochondrial protein and exhibited a significantly higher total thermogenic activity in BAT. Type I iodothyronine 5 deiodinas(EC 3.8.1.4) activity in BAT peaked at birth, as did hepatic iodothyronine Sdeiodinase activity and was significantly greater in lambs born to under-fed shorn ewes, which exhibited a higher plasma triiodothyronine concentration. Chronic maternal adaptations to prolonged cold exposure appear to enable pregnant ewes to compensate for the negative effects of under-feeding on fetal growth and development


1995 ◽  
Vol 269 (1) ◽  
pp. R38-R47 ◽  
Author(s):  
J. M. Matz ◽  
M. J. Blake ◽  
H. M. Tatelman ◽  
K. P. Lavoi ◽  
N. J. Holbrook

The accumulation of heat shock proteins (HSPs) after the exposure of cells or organisms to elevated temperatures is well established. It is also known that a variety of other environmental and cellular metabolic stressors can induce HSP synthesis. However, few studies have investigated the effect of cold temperature on HSP expression. Here we report that exposure of Institute of Cancer Research (ICR) mice to cold ambient temperatures results in a tissue-selective induction of HSPs in brown adipose tissue (BAT) coincident with the induction of mitochondrial uncoupling protein synthesis. Cold-induced HSP expression is associated with enhanced binding of heat shock transcription factors to DNA, similar to that which occurs after exposure of cells or tissues to heat and other metabolic stresses. Adrenergic receptor antagonists were found to block cold-induced HSP70 expression in BAT, whereas adrenergic agonists induced BAT HSP expression in the absence of cold exposure. These findings suggest that norepinephrine, released in response to cold exposure, induces HSP expression in BAT. Norepinephrine appears to initiate transcription of HSP genes after binding to BAT adrenergic receptors through, as yet, undetermined signal transduction pathways. Thermogenesis results from an increase in activity and synthesis of several metabolic enzymes in BAT of animals exposed to cold challenge. The concomitant increase in HSPs may function to facilitate the translocation and activity of the enzymes involved in this process.


2014 ◽  
Vol 222 (3) ◽  
pp. 327-339 ◽  
Author(s):  
Abdoulaye Diané ◽  
Nikolina Nikolic ◽  
Alexander P Rudecki ◽  
Shannon M King ◽  
Drew J Bowie ◽  
...  

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a widely distributed neuropeptide that acts as a neurotransmitter, neuromodulator, neurotropic factor, neuroprotectant, secretagogue,and neurohormone. Owing to its pleiotropic biological actions, knockout ofPacap(Adcyap1) has been shown to induce several abnormalities in mice such as impaired thermoregulation. However, the underlying physiological and molecular mechanisms remain unclear. A previous report has shown that cold-exposedPacapnull mice cannot supply appropriate levels of norepinephrine (NE) to brown adipocytes. Therefore, we hypothesized that exogenous NE would rescue the impaired thermogenic response ofPacapnull mice during cold exposure. We compared the adaptive thermogenic capacity ofPacap−/−toPacap+/+mice in response to NE when housed at room temperature (24 °C) and after a 3.5-week cold exposure (4 °C). Biochemical parameters, expression of thermogenic genes, and morphological properties of brown adipose tissue (BAT) and white adipose tissue (WAT) were also characterized. Results showed that there was a significant effect of temperature, but no effect of genotype, on the resting metabolic rate in conscious, unrestrained mice. However, the normal cold-induced increase in the basal metabolic rate and NE-induced increase in thermogenesis were severely blunted in cold-exposedPacap−/−mice. These changes were associated with altered substrate utilization, reduced β3-adrenergic receptor (β3-Ar(Adrb3)) and hormone-sensitive lipase (Hsl(Lipe)) gene expression, and increased fibroblast growth factor 2 (Fgf2) gene expression in BAT. Interestingly,Pacap−/−mice had depleted WAT depots, associated with upregulated uncoupling protein 1 expression in inguinal WATs. These results suggest that the impairment of adaptive thermogenesis inPacapnull mice cannot be rescued by exogenous NE perhaps in part due to decreased β3-Ar-mediated BAT activation.


2020 ◽  
Vol 245 (3) ◽  
pp. 343-356 ◽  
Author(s):  
Chunchun Wei ◽  
Xianhua Ma ◽  
Kai Su ◽  
Shasha Qi ◽  
Yuangang Zhu ◽  
...  

Brown adipose tissue (BAT) plays a critical role in energy expenditure by uncoupling protein 1 (UCP1)-mediated thermogenesis. Carbohydrate response element-binding protein (ChREBP) is one of the key transcription factors regulating de novo lipogenesis (DNL). As a constitutively active form, ChREBP-β is expressed at extremely low levels. Up to date, its functional relevance in BAT remains unclear. In this study, we show that ChREBP-β inhibits BAT thermogenesis. BAT ChREBP-β mRNA levels were elevated upon cold exposure, which prompted us to generate a mouse model overexpressing ChREBP-β specifically in BAT using the Cre/LoxP approach. ChREBP-β overexpression led to a whitening phenotype of BAT at room temperature, as evidenced by increased lipid droplet size and decreased mitochondrion content. Moreover, BAT thermogenesis was inhibited upon acute cold exposure, and its metabolic remodeling induced by long-term cold adaptation was significantly impaired by ChREBP-β overexpression. Mechanistically, ChREBP-β overexpression downregulated expression of genes involved in mitochondrial biogenesis, autophagy, and respiration. Furthermore, thermogenic gene expression (e.g. Dio2, UCP1) was markedly inhibited in BAT by the overexpressed ChREBP-β. Put together, our work points to ChREBP-β as a negative regulator of thermogenesis in brown adipocytes.


1985 ◽  
Vol 231 (3) ◽  
pp. 761-764 ◽  
Author(s):  
R Bazin ◽  
D Ricquier ◽  
F Dupuy ◽  
J Hoover-Plow ◽  
M Lavau

The thermogenic capacity of brown adipose tissue has been investigated in I-strain mice to determine whether this tissue could play a role in the lower efficiency of food utilization reported in this strain of mice. (1) As compared with C57BL mice (a control strain), interscapular-brown-adipose-tissue weight and lipid percentage were decreased by 40% and 13% respectively in I-strain mice. (2) Mitochondrial protein content and cytochrome c oxidase activity were similar in the two strains, but the number of mitochondrial GDP-binding sites and uncoupling-protein content were increased by 2-fold in I-strain mice. (3) Fatty acid synthetase and citrate-cleavage enzyme (units/mg of protein) were 3-fold higher in the brown adipose tissue of I-strain mice. These results indicate that I-strain mice possess a very active brown adipose tissue. This enhanced capacity of energy dissipation in brown adipose tissue could contribute to the decreased capacity of I-strain mice to store adipose tissue.


Endocrinology ◽  
2003 ◽  
Vol 144 (11) ◽  
pp. 4831-4840 ◽  
Author(s):  
Márcio Pereira-da-Silva ◽  
Márcio A. Torsoni ◽  
Hugo V. Nourani ◽  
Viviane D. Augusto ◽  
Cláudio T. Souza ◽  
...  

Abstract Short-term cold exposure of homeothermic animals leads to higher thermogenesis and food consumption accompanied by weight loss. An analysis of cDNA-macroarray was employed to identify candidate mRNA species that encode proteins involved in thermogenic adaptation to cold. A cDNA-macroarray analysis, confirmed by RT-PCR, immunoblot, and RIA, revealed that the hypothalamic expression of melanin-concentrating hormone (MCH) is enhanced by exposure of rats to cold environment. The blockade of hypothalamic MCH expression by antisense MCH oligonucleotide in cold-exposed rats promoted no changes in feeding behavior and body temperature. However, MCH blockade led to a significant drop in body weight, which was accompanied by decreased liver glycogen, increased relative body fat, increased absolute and relative interscapular brown adipose tissue mass, increased uncoupling protein 1 expression in brown adipose tissue, and increased consumption of lean body mass. Thus, increased hypothalamic MCH expression in rats exposed to cold may participate in the process that allows for efficient use of energy for heat production during thermogenic adaptation to cold.


Author(s):  
Chang-Hyung Lee ◽  
Young-A Choi ◽  
Sung-Jin Heo ◽  
Parkyong Song

Brown adipose tissue (BAT) plays an important role in thermogenic regulation, which contributes to alleviating diet-induced obesity through uncoupling protein 1 (UCP1) expression. While cold exposure and physical exercise are known to increase BAT development and UCP1 expression, the contribution of hyperbaric oxygen (HBO) therapy to BAT maturation remains largely unknown. Here, we show that HBO treatment sufficiently increases BAT volumes and thermogenic protein levels in Sprague-Dawley rats. Through 18F-FDG PET/CT analysis, we found that exposure to high-pressure oxygen (1.5–2.5 ATA) for 7 consecutive days increased radiolabeled glucose uptake and BAT development to an extent comparable to cold exposure. Consistent with BAT maturation, thermogenic protein levels, such as those of UCP1 and peroxisome proliferator-activated receptor γ coactivator 1α (PGC−1α), were largely increased by HBO treatment. Taken together, we suggest HBO therapy as a novel method of inducing BAT development, considering its therapeutic potential for the treatment of metabolic disorders.


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