Enhanced gene expression of endothelial nitric oxide  synthase in brown adipose tissue during cold exposure

It has been shown that norepinephrine (NE) can mediate vasodilatation by stimulating the production of nitric oxide (NO) in brown adipose tissue (BAT), resulting in an increase in BAT blood flow. We speculated that constitutive NO synthase (NOS) is involved in this NO production. However, it is not known whether constitutive NOS is expressed in BAT. To answer this question, we assessed the expression of two types of constitutive NOS, endothelial (eNOS) and neuronal NOS (nNOS), in BAT of rats. eNOS was abundantly expressed in both BAT and isolated brown adipocytes, whereas nNOS was not. Cold exposure, which is known to stimulate NE release from sympathetic nerve terminals in BAT, led to a significant increase in eNOS mRNA in this tissue. In contrast, very low levels of inducible NOS (iNOS) mRNA were expressed, and cold stimulation failed to increase iNOS mRNA levels in BAT. These results suggest that eNOS is the primary isoform that is responsible for NO production in BAT and that its expression may be under sympathetic control.

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ChREBP-β regulates thermogenesis in brown adipose tissue

Journal of Endocrinology ◽

10.1530/joe-19-0498 ◽

2020 ◽

Vol 245 (3) ◽

pp. 343-356 ◽

Cited By ~ 1

Author(s):

Chunchun Wei ◽

Xianhua Ma ◽

Kai Su ◽

Shasha Qi ◽

Yuangang Zhu ◽

...

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

Cold Exposure ◽

Uncoupling Protein ◽

Critical Role ◽

Active Form ◽

Negative Regulator ◽

Mrna Levels ◽

Brown Adipose ◽

Metabolic Remodeling

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.

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Abstract 13115: Nitric Oxide Differentially Regulates White and Brown Adipogenesis Through Effects on Thermogenesis and Mitochondrial Biogenesis (Best of Basic Science Abstract)

Circulation ◽

10.1161/circ.132.suppl_3.13115 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Paul Huang ◽

Sylvia Lee-Huang

Keyword(s):

Nitric Oxide ◽

Adipose Tissue ◽

Brown Adipose Tissue ◽

Mitochondrial Biogenesis ◽

Cold Exposure ◽

Adipocyte Differentiation ◽

Metabolic Effects ◽

Gain Of Function ◽

Brown Adipose ◽

Brown Adipogenesis

Introduction: In addition to its roles as a vascular signaling molecule, nitric oxide (NO) plays roles in metabolism. Mice deficient in eNOS are overweight and develop insulin resistance. It is not known whether the metabolic effects are due to primary roles of NO, or to increased visceral adiposity, leading to secondary metabolic changes. Hypothesis: We hypothesized that NO plays distinct and separable primary roles in white and brown adipogenesis, which underlie the effects on adiposity, energy metabolism, and expression of thermogenic genes. Methods: We exposed wild-type and mice carrying specific gain of function and loss of function eNOS mutations to cold at 4C for 48 hours and assessed expression of thermogenic gene programs in white and brown adipose tissue. To study cell autonomous effects, we differentiated adipocyte precursors from brown and white fat in the presence of NOS inhibitors and NO donors, as well as with siRNA to knockdown eNOS expression. Results: Cold exposure resulted in upregulation of the thermogenic gene program in brown adipose tissue. Animals carrying a gain of function mutation in eNOS showed increased UCP1 expression even without cold exposure. Induction of thermogenic genes was more pronounced in the animals with gain of function eNOS mutation. Differentiation of adipocyte precursors showed effects of eNOS on adipogenesis. Cells treated with the pharmacologic blockade (L-NAME and L-NA) as well as genetic knockdown (siRNA) showed dose-dependent inhibition of adipocyte differentiation. MitoTracker Red CMXRos staining showed that treatment with the NO donor SNAP increases mitochondrial biogenesis, while L-NAME decreases mitochondrial biogenesis. Conclusions: We show that eNOS-derived NO plays distinct and separable roles in white and brown adipogenesis. In brown adipocytes, eNOS regulates the expression of the thermogenic gene program, with upregulation of expression even without cold exposure, and greater increase in response to cold. In white adipocytes, eNOS-derived NO is required for adipocyte differentiation and mitochondrial biogenesis.

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PPARγ activation attenuates cold-induced upregulation of thyroid status and brown adipose tissue PGC-1α and D2

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00299.2012 ◽

2012 ◽

Vol 303 (12) ◽

pp. R1277-R1285 ◽

Cited By ~ 11

Author(s):

William T. Festuccia ◽

Pierre-Gilles Blanchard ◽

Thiago B. Oliveira ◽

Juliana Magdalon ◽

Vivian A. Paschoal ◽

...

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

Cold Exposure ◽

Sympathetic Activity ◽

Mrna Levels ◽

Thyroid Status ◽

Iodothyronine Deiodinase ◽

Camp Content ◽

Adrenergic Signaling ◽

Brown Adipose

Here, we investigated whether pharmacological PPARγ activation modulates key early events in brown adipose tissue (BAT) recruitment induced by acute cold exposure with the aim of unraveling the interrelationships between sympathetic and PPARγ signaling. Sprague-Dawley rats treated or not with the PPARγ ligand rosiglitazone (15 mg·kg−1·day−1, 7 days) were kept at 23°C or exposed to cold (5°C) for 24 h and evaluated for BAT gene expression, sympathetic activity, thyroid status, and adrenergic signaling. Rosiglitazone did not affect the reduction in body weight gain and the increase in feed efficiency, V̇o2, and BAT sympathetic activity induced by 24-h cold exposure. Rosiglitazone strongly attenuated the increase in serum total and free T4 and T3 levels and BAT iodothyronine deiodinase type 2 (D2) and PGC-1α mRNA levels and potentiated the reduction in BAT thyroid hormone receptor (THR) β mRNA levels induced by cold. Administration of T3 to rosiglitazone-treated rats exacerbated the cold-induced increase in energy expenditure but did not restore a proper activation of D2 and PGC-1α, nor further increased uncoupling protein 1 expression. Regarding adrenergic signaling, rosiglitazone did not affect the changes in BAT cAMP content and PKA activity induced by cold. Rosiglitazone alone or in combination with cold increased CREB binding to DNA, but it markedly reduced the expression of one of its major coactivators, CREB binding protein. In conclusion, pharmacological PPARγ activation impairs short-term cold elicitation of BAT adrenergic and thyroid signaling, which may result in abnormal tissue recruitment and thermogenic activity.

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Increased expression of glucose transporter GLUT-4 in brown adipose tissue of fasted rats after cold exposure

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1993.264.6.e890 ◽

1993 ◽

Vol 264 (6) ◽

pp. E890-E895 ◽

Cited By ~ 14

Author(s):

Y. Shimizu ◽

H. Nikami ◽

K. Tsukazaki ◽

U. F. Machado ◽

H. Yano ◽

...

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

Glucose Uptake ◽

Cold Exposure ◽

De Novo ◽

Mrna Levels ◽

Glut 4 ◽

Increase Glucose Uptake ◽

Brown Adipose ◽

Stimulation Of

Cold exposure has been shown to increase glucose uptake specifically in brown adipose tissue (BAT), the major site for sympathetically controlled metabolic heat production. In this study, the relationship between glucose uptake and glucose transporters (GLUT) was examined in rats exposed to cold for various periods. To minimize the stimulatory effect of circulating insulin, all animals were starved for 20-24 h before the measurements. Acute (4 h) cold exposure had no effect on protein and mRNA levels of GLUT-4, the predominant isoform of GLUT in BAT, despite a significant increase in cellular glucose uptake. Prolonged (1-10 days) cold exposure produced a parallel increase in GLUT-4 expression and glucose uptake in BAT. In contrast, cold exposure had no noticeable effect on GLUT-1, another isoform of GLUT in BAT, and on GLUT-4 in other insulin-sensitive tissues such as white adipose tissue and muscles. The increased glucose uptake and GLUT-4 expression were completely abolished after surgical sympathetic denervation. These findings suggest that cold exposure increases glucose uptake in BAT by at least two distinct mechanisms, both of which are dependent on sympathetic nerve: 1) an increase in the amount of GLUT-4 due to the stimulation of its de novo synthesis, and 2) an increase without stimulation of GLUT synthesis, probably due to the change in the transport activity of GLUT-4 and/or its translocation from an intracellular pool to the plasma membrane.

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Expression of glycerokinase in brown adipose tissue is stimulated by the sympathetic nervous system

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00764.2002 ◽

2003 ◽

Vol 284 (6) ◽

pp. R1536-R1541 ◽

Cited By ~ 27

Author(s):

W. T. L. Festuccia ◽

R. Guerra-Sá ◽

N. H. Kawashita ◽

M. A. R. Garófalo ◽

E. A. Evangelista ◽

...

Keyword(s):

Enzyme Activity ◽

Adipose Tissue ◽

Brown Adipose Tissue ◽

Cold Exposure ◽

Mrna Levels ◽

Interscapular Brown Adipose Tissue ◽

Fourfold Increase ◽

Norepinephrine Infusion ◽

Brown Adipose

The effect of cold exposure (4°C) or prolonged norepinephrine infusion on the activity and mRNA levels of glycerokinase (GyK) was investigated in rat interscapular brown adipose tissue (BAT). Cold exposure for 12 and 24 h induced increases of 30% and 100%, respectively, in the activity of BAT GyK, which was paralleled by twofold and fourfold increase in enzyme mRNA levels. BAT hemidenervation resulted in reductions of 50% and 30% in GyK activity and in mRNA levels, respectively, in denervated pads from rats kept at 25°C, and suppressed in these pads the cold-induced increases in both GyK activity and mRNA levels. The increase in GyK activity induced by cold exposure was not affected by phenoxybenzamine, but was markedly inhibited by previous administration of propranolol or actinomycin D. BAT GyK activity did not change significantly after 6 h of continuous subcutaneous infusion of norepinephrine (20 μg/h), but increased twofold and fourfold after 12 and 24 h, with no further increase after 72 h of infusion. Norepinephrine infusion also activated mRNA production, but the effect was comparatively smaller than that on enzyme activity. β-Adrenergic agonists also stimulated GyK activity with the following relative magnitude of response: CL316243 (β3) > isoproterenol (non-selective) > dobutamine (β1). In vitro rates of incorporation of glycerol into glyceride-glycerol were increased in BAT from rats exposed to cold. The data suggest that in conditions of a sustained increase in BAT sympathetic flow there is a stimulation of GyK gene expression at the pretranslational level, with increased enzyme activity, mediated by β-adrenoreceptors, mainly β3.

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Comparing the protective effects of resveratrol, curcumin and sulforaphane against LPS/IFN-γ-mediated inflammation in doxorubicin-treated macrophages

Scientific Reports ◽

10.1038/s41598-020-80804-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Haidy A. Saleh ◽

Eman Ramdan ◽

Mohey M. Elmazar ◽

Hassan M. E. Azzazy ◽

Anwar Abdelnaser

Keyword(s):

Nitric Oxide ◽

Inflammatory Response ◽

Raw 264.7 Cells ◽

Inos Mrna ◽

No Production ◽

Raw 264.7 ◽

Mrna Levels ◽

Protective Effects ◽

Tnf Α ◽

Ifn Γ

AbstractDoxorubicin (DOX) chemotherapy is associated with the release of inflammatory cytokines from macrophages. This has been suggested to be, in part, due to DOX-mediated leakage of endotoxins from gut microflora, which activate Toll-like receptor 4 (TLR4) signaling in macrophages, causing severe inflammation. However, the direct function of DOX on macrophages is still unknown. In the present study, we tested the hypothesis that DOX alone is incapable of stimulating inflammatory response in macrophages. Then, we compared the anti-inflammatory effects of curcumin (CUR), resveratrol (RES) and sulforaphane (SFN) against lipopolysaccharide/interferon-gamma (LPS/IFN-γ)-mediated inflammation in the absence or presence of DOX. For this purpose, RAW 264.7 cells were stimulated with LPS/IFN-γ (10 ng/mL/10 U/mL) in the absence or presence of DOX (0.1 µM). Our results showed that DOX alone is incapable of stimulating an inflammatory response in RAW 264.7 macrophages. Furthermore, after 24 h of incubation with LPS/IFN-γ, a significant increase in tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and inducible nitric oxide synthase (iNOS) mRNA levels was observed. Similarly, nitric oxide (NO) production and TNF-α and IL-6 protein levels were significantly upregulated. Moreover, in LPS/IFN-γ-treated macrophages, the microRNAs (miRNAs) miR-146a, miR-155, and miR-21 were significantly overexpressed. Interestingly, upon testing CUR, RES, and SFN against LPS/IFN-γ-mediated inflammation, only SFN was able to significantly reverse the LPS/IFN-γ-mediated induction of iNOS, TNF-α and IL-6 and attenuate miR-146a and miR-155 levels. In conclusion, SFN, at the transcriptional and posttranscriptional levels, exhibits potent immunomodulatory action against LPS/IFN-γ-stimulated macrophages, which may indicate SFN as a potential treatment for DOX-associated inflammation.

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Chronic cold exposure induces autophagy to promote fatty acid oxidation, mitochondrial turnover, and thermogenesis in brown adipose tissue

iScience ◽

10.1016/j.isci.2021.102434 ◽

2021 ◽

pp. 102434

Author(s):

Winifred W. Yau ◽

Kiraely Adam Wong ◽

Jin Zhou ◽

Nivetha Kanakaram Thimmukonda ◽

Yajun Wu ◽

...

Keyword(s):

Adipose Tissue ◽

Fatty Acid ◽

Brown Adipose Tissue ◽

Fatty Acid Oxidation ◽

Cold Exposure ◽

Acid Oxidation ◽

Brown Adipose ◽

Mitochondrial Turnover

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Reduced brown adipose tissue activity during cold exposure is a metabolic feature of the human thrifty phenotype

Metabolism ◽

10.1016/j.metabol.2021.154709 ◽

2021 ◽

Vol 117 ◽

pp. 154709 ◽

Cited By ~ 1

Author(s):

Tim Hollstein ◽

Karyne Vinales ◽

Kong Y. Chen ◽

Aaron M. Cypess ◽

Alessio Basolo ◽

...

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

Cold Exposure ◽

Thrifty Phenotype ◽

Brown Adipose ◽

Metabolic Feature ◽

Brown Adipose Tissue Activity

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Changes in β1- and β2-adrenergic receptor mRNA levels in brown adipose tissue and heart of hypothyroid rats

Biochemical Journal ◽

10.1042/bj2770625 ◽

1991 ◽

Vol 277 (3) ◽

pp. 625-629 ◽

Cited By ~ 30

Author(s):

J P Revelli ◽

R Pescini ◽

P Muzzin ◽

J Seydoux ◽

M G Fitzgerald ◽

...

Keyword(s):

Adipose Tissue ◽

Brown Adipose Tissue ◽

Adrenergic Receptor ◽

State Level ◽

Total Density ◽

Mrna Levels ◽

Interscapular Brown Adipose Tissue ◽

Brown Adipose ◽

Displacement Experiments ◽

Beta 2

The aim of the present work was to study the effect of hypothyroidism on the expression of the beta-adrenergic receptor (beta-AR) in interscapular brown adipose tissue and heart. The total density of plasma membrane beta-AR per tissue is decreased by 44% in hypothyroid rat interscapular brown adipose tissue and by 55% in hypothyroid rat heart compared with euthyroid controls. The effects of hypothyroidism on the density of both beta 1- and beta 2-AR subtypes were also determined in competition displacement experiments. The densities of beta 1- and beta 2-AR per tissue are decreased by 50% and 48% respectively in interscapular brown adipose tissue and by 52% and 54% in the heart. Northern blot analysis of poly(A)+ RNA from hypothyroid rat interscapular brown adipose tissue demonstrated that the levels of beta 1- and beta 2-AR mRNA per tissue are decreased by 73% and 58% respectively, whereas in hypothyroid heart, only the beta 1-AR mRNA is decreased, by 43%. The effect of hypothyroidism on the beta 1-AR mRNA is significantly more marked in the interscapular brown adipose tissue than in the heart. These results indicate that beta-AR mRNA levels are differentially regulated in rat interscapular brown adipose tissue and heart, and suggest that the decrease in beta-AR number in interscapular brown adipose tissue and heart of hypothyroid animals may in part be explained by a decreased steady-state level of beta-AR mRNA.

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