UCP3 mRNA Expression Research Articles

Low-level lasers affect uncoupling protein gene expression in skin and skeletal muscle tissues

Wavelength, frequency, power, fluence, and emission mode determine the photophysical, photochemical, and photobiological responses of biological tissues to low-level lasers. Free radicals are involved in these responses acting as second messengers in intracellular signaling processes. Irradiated cells present defenses against these chemical species to avoid unwanted effects, such as uncoupling proteins (UCPs), which are part of protective mechanisms and minimize the effects of free radical generation in mitochondria. In this work UCP2 and UCP3 mRNA gene relative expression in the skin and skeletal muscle tissues of Wistar rats exposed to low-level red and infrared lasers was evaluated. Samples of the skin and skeletal muscle tissue of Wistar rats exposed to low-level red and infrared lasers were withdrawn for total RNA extraction, cDNA synthesis, and the evaluation of gene expression by quantitative polymerase chain reaction. UCP2 and UCP3 mRNA expression was differently altered in skin and skeletal muscle tissues exposed to lasers in a wavelength-dependent effect, with the UCP3 mRNA expression dose-dependent. Alteration on UCP gene expression could be part of the biostimulation effect and is necessary to make cells exposed to red and infrared low-level lasers more resistant or capable of adapting in damaged tissues or diseases.

Effects of resveratrol, grape juice or red wine consumption Irisin levels and fibronectin type III domain containing protein 5 and uncoupoling protein gene expression modulation in rats

Summary Objectives The aim was investigate resveratrol, grape juice, or red wine effects on FNDC5 and UCP2 gene expression on muscle and adipose tissue of Wistar rats receiving a high-fat diet. Methods Five groups of female Wistar rats formed with five animals in each (Control Group-CG, High-Fat Group-HFG-20%, Grape Juice Group-GJG; Red Wine Group-RWG and Resveratrol Group-RG) were treated for 2 months. At the end, adipose and muscle tissues were collected, FNDC5 and UCP2 mRNA expressions were obtained by using real-time polymerase chain reaction. Irisin levels were assessed through ELISA. For comparison: two way ANOVA, using Duncan as post-test. Results FNDC5 mRNA expression was increased in RG and GJG muscle (p Conclusion Resveratrol and grape juice were able to increase muscle tissue FNDC5 gene expression, and high-fat diet, red wine and resveratrol, increased UCP2 gene expression in this tissue. Grape juice was capable of increasing adipose tissue UCP2 gene expression. High-fat diet, isolated or associated to beverages rich in polyphenols, have decreased FNDC5 gene expression in adipose tissue. Nevertheless, the interventions did not affect irisin levels.

The Effect of Growth Hormone on Lipid Accumulation or Maturation in Adipocytes

Background: Adipogenesis of adipocytes includes two stages: initiation and maturation. Growth hormone (GH) secretion is decreased in obese subjects and GH levels are inversely correlated with abdominal fat mass. The effects of growth hormone (GH) on lipids accumulation or maturation of adipocytes remains elusive. Methods: In the present study, effect of GH on lipid accumulation in vitro and in vivo was examined. cDNA microarray, quantitative real time-PCR (qPCR) and western blotting was used to analyze the expression of genes related to adipocyte lipid accumulation or degradation in pre- or mature 3T3-F442A adipocytes treated with GH and in epididymal adipose tissue of C57BL/6 mice administrated with GH. Level of adiponectin in supernatants of cultured F442A adipocytes was determined by enzyme-linked immune-sorbent assay. Results: We found that in 3T3-F442A especially 6 days post initiation of adipogenesis, GH intervention resulted in decreased expression of adipocyte maturation regulators (C/EBPα, PPARγ) and prominent genes related to lipid synthesis such as FAS and FABP, while the expression of UCP1 was markedly enhanced. cDNA microarray analysis and qPCR showed that the expression of SOCS2 and Adipor2 was increased under GH-treatment in mature 3T3-F442A adipocytes. GH treatment increased the mRNA expression of adiponectin and UCP1 in mature adipocytes. The above results were confirmed by in vivo study. Conclusions: GH potentially negatively modulates the maturation and accumulation of lipid in adipocytes.

Estrogen Receptor α and β in Mouse: Adipose-Derived Stem Cell Proliferation, Migration, and Brown Adipogenesis In Vitro

Background/Aims: Adipose-derived stem cells (ASCs) belong to mesenchymal stem cells and may play a potential role as seeding cells in stem cell transplantation. To be able to exploit stem cells as therapeutic tool, their defects in some important cellular functions, such as low survival rate and cellular activity, should be considered. This is especially the case for stem cells that are intended for transplantation. Of note, stem cell responses to hormones should be considered since estrogen is known to play a critical role in stem cell behavior. However, different impacts of the estrogen receptor (ER) types α and β have not been fully determined in ASC function. In this study, we investigated effects of ERα and ERβ on ASC proliferation, migration, as well as in adipogenesis. Methods: ASCs obtained from mice were cultured with 100nM ERα or ERβ agonist PPT and DPN, respectively. The ERα and ERβ antagonist ICI 182,780 (100nM) was used as control. Results: Compared to ERβ, ERα appears more potent in improving ASC proliferation and migration. Investigation of adipogenesis revealed that ERβ played a significant role in suppressing ASC-mediated brown tissue adipogenesis which is in contrast to ERα. These results correlated with reduced mRNA expression of UCP-1, PGC-1α and PPAR-γ. Conclusions: ERα plays a more critical role in promoting ASC proliferation and migration while ERβ is more potent in suppressing ASC brown adipose tissue differentiation mediated by decreased UCP-1, PGC-1α and PPAR-γ expression.

A single oral dose of flavan-3-ols enhances energy expenditure by sympathetic nerve stimulation in mice

Numerous clinical studies have found that ingestion of chocolate reduces the risk of metabolic syndrome, however, the mechanisms were remain unclear. We have reported that a single dose of a flavan-3-ol fraction derived from cocoa (FL) enhanced energy expenditure (EE) and increased the mRNA expression levels of uncoupling proteins (UCPs) and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), and the protein level of phosphorylated AMP-activated protein kinase (AMPK)α in tissues, along with plasma adrenaline level. In the present study, we examined whether the EE enhancing activity of FL is mediated by adrenergic effect using several adrenalin receptor (AR) blockers. In the first study, mice were butoxamine, as β2AR blocker, with vehicle or 10mg/kg FL orally. We found that pretreatment with butoxamine prevented the increases of EE, the mRNA expression of UCP-3, and phosphorylated AMPKα that were induced in the gastrocnemius muscle of mice by 10mg/kg FL. Secondly, mice were given SR52930, as β3AR blocker. Pretreatment with SR52930 prevented the increases of EE, the mRNA expression of UCP-3, and phosphorylated AMPKα that were induced in the gastrocnemius muscle of mice by 10mg/kg FL. Pretreatment with a combination of both blockers also reduced the increments in mRNA expression levels of UCPs and PGC-1α, however, phosphorylated AMPKα in skeletal muscle was rather increased. These results suggest that the ability of a single oral dose of FL to enhance metabolic activity is mediated by sympathetic nerve system (SNS).

Insulin sensitizes FGF21 in glucose and lipid metabolisms via activating common AKT pathway.

Previous studies reveal that fibroblast growth factor 21 (FGF21) sensitizes insulin to achieve a synergy in regulating glucose metabolism. Here, we report that insulin sensitizes FGF21 in regulating both glucose and lipid metabolisms. db/db diabetic mice were subcutaneously administrated once a day for 6weeks. Effective dose of insulin (1U) could control blood glucose level of the db/db mice for maximum of 2h, increased the body weight of the db/db mice and did not improve serum lipid parameters. In contrast, effective dose of FGF21 (0.5mg/kg) could maintain blood glucose of the db/db mice at normal level for at least 24h, repressed the weight gain of the mice and significantly improved lipid parameters. Ineffective doses of FGF21 (0.125mg/kg) and insulin had no effect on blood glucose level of the db/db mice after 24h administration, body weight or lipid parameters. However, combination of the two ineffective doses could maintain blood glucose level of the db/db mice for at least 24h, suppressed weight gain and significantly improved lipid parameters. These results suggest that insulin sensitizes FGF21 in regulating both glucose and lipid metabolism. The results aimed to study the molecular basis of FGF21 sensitization indicates that combination of the two ineffective doses increased the mRNA expression of glut1, glut4, β-Klotho, sirt1, pgc-1α, ucp-1 and AKT phosphorylation, decreased fasn. The results demonstrate that insulin sensitizes FGF21 through elevating the phosphorylation of common gene Akt and amplifying FGF21 downstream signaling, including increasing expression of glut1 sirt1, pgc-1α, ucp-1, and decreasing fasn expression. In summary, we reports herein for the first time that insulin sensitizes FGF21 to achieve a synergy in regulating glucose and lipid metabolism. Along with previous studies, we conclude that the synergistic effect between FGF21 and insulin is realized through mutual sensitization.

Overnutrition during lactation leads to impairment in insulin signaling, up-regulation of GLUT1 and increased mitochondrial carbohydrate oxidation in heart of weaned mice

Several studies have demonstrated that overnutrition during early postnatal period can increase the long-term risk of developing obesity and cardiac disorders, yet the short-term effects of postnatal overfeeding in cardiac metabolism remains unknown. The aim of our study was to investigate the cardiac metabolism of weaned mice submitted to overnutrition during lactation, particularly as to mitochondrial function, substrate preference and insulin signaling. Postnatal overfeeding was induced by litter size reduction in mice at postnatal day 3. At 21 days of age (weaning), mice in the overfed group (OG) presented biometric and biochemical parameters of obesity, including increased body weight, visceral fat, liver weight and increased left ventricle weight/tibia length ratio; indicating cardiac hypertrophy, hyperglycemia, hyperinsulinemia and increased liver glycogen content compared to control group. In the heart, we detected impaired insulin signaling, mainly due to decreased IRβ, pTyr-IRS1, PI3K, GLUT4 and pAkt/Akt and increased PTP1B, GLUT1 and pAMPKα/AMPKα content. Activities of lactate dehydrogenase and citrate synthase were increased, accompanied by enhanced carbohydrate oxidation, as observed by high-resolution respirometry. Moreover, OG hearts had lower CPT1, PPARα and increased UCP2 mRNA expression, associated with increased oxidative stress (4-HNE content), BAX/BCL2 ratio and cardiac fibrosis. Ultrastructural analysis of OG hearts demonstrated mild mitochondrial damage without alterations in OXPHOS complexes. In conclusion, overnutrition during early life induces short-term metabolic disturbances, impairment in heart insulin signaling, up-regulates GLUT-1 and switch cardiac fuel preference in juvenile mice.

Cold Exposure Partially Corrects Disturbances in Lipid Metabolism in a Male Mouse Model of Glucocorticoid Excess.

High glucocorticoid concentrations are accompanied by metabolic side effects such as high plasma triglyceride (TG) concentrations. Liver, brown adipose tissue (BAT) and white adipose tissue are important regulators of plasma TG. Exposure to 4°C reduces plasma TG concentrations, and we therefore aimed to study the interaction between glucocorticoid excess and 24 hours of exposure to 4°C on lipid metabolism. For this, mice were implanted with 50-mg corticosterone or control pellets and housed for 24 hours at 23°C or 4°C 1 week later, after which various aspects of TG metabolism in liver, BAT, and white adipose tissue were studied. Corticosterone treatment resulted in a 3.8-fold increase of plasma TG concentrations. Increased TG was normalized by cold exposure, an effect still present 24 hours after cold exposure. Corticosterone treatment increased hepatic TG content by 3.5-fold and provoked secretion of large, TG-rich very low density lipoprotein particles. Cold exposure reduced very low density lipoprotein-TG secretion by approximately 50%. Corticosterone strongly decreased BAT activity: BAT weight increased by 3.5-fold, whereas uncoupling protein 1 (Ucp1) mRNA expression and Ucp1 protein content of BAT were reduced by 75% and 60%, respectively. Cold exposure partially normalized these parameters of BAT activity. The uptake of TG by BAT was not affected by corticosterone treatment but was increased 4.5-fold upon cold exposure. In conclusion, cold exposure normalizes corticosterone-induced hypertriglyceridemia, at least partly via activating BAT.

Ginsenoside Rb1 promotes browning through regulation of PPARγ in 3T3-L1 adipocytes

Browning of white adipocyte tissue (WAT) has received considerable attention due to its potential implication in preventing obesity and related comorbidities. Ginsenoside Rb1 is reported to improve glycolipid metabolism and reduce body weight in obese animals. However whether the body reducing effect mediates by browning effect remains unclear. For this purpose, 3T3-L1 adipocytes were used to study the effect of ginsenoside Rb1 on browning adipocytes specific genes and oxygen consumptions. The results demonstrate that 10 μM of ginsenoside Rb1 increases basal glucose uptake and promoted browning evidenced by significant increases in mRNA expressions of UCP-1, PGC-1α and PRDM16 in 3T3-L1 mature adipocytes. Further, ginsenoside Rb1 also increases PPARγ activity. And the browning effect is abrogated by GW9692, a PPARγ antagonist. In addition, ginsenoside Rb1 increases basal respiration rate, ATP production and uncoupling capacity in 3T3-L1 adipocytes. Those effects are also blunted by GW9692. The results suggest that ginsenoside Rb1 promote browning of 3T3-L1 adipocytes through induction of PPARγ. Our finding offer a new source to discover browning agonists and also useful to understand and extend the applications of ginseng and its constituents.

GLP-1 contributes to increases in PGC-1α expression by downregulating miR-23a to reduce apoptosis

GLP-1 can help to overcome problems of liver cells metabolism, not only pancreatic cell. But the explicit mechanism of this effect remains unclear. In recent years, microRNAs have received the attention of researchers and some microRNAs have important implications for diabetes. The mitochondrial protective gene PGC-1α is also closely related to diabetes, and UCP2 is related to anti-mitochondrial oxidative stress, but the mechanism of action of these genes is unclear. In this study, we used HepG2 cell line and used the cell counting kit (CCK) to measure the cell viability with GLP-1(7–36) and/or glucotoxicity. To investigate alterations in gene expression resulting from incubation with GLP-1 (7–36) or hyperglycaemia, the RNA expression levels of miR-23a, PGC-1α, Bak, Bax and UCP2 were quantified using real-time PCR. The protein levels of PGC-1α were determined by western blot. The role of miR-23a in the regulation of PGC-1α was further assessed through cell transfection to downregulate of miR-23a expression. In this study, the viability of HepG2 hepatocytes was decreased under hyperglycaemia, but incubation with 10 nmol/L GLP-1 (7–36) amide for 24 h significantly increased the viability and decreased the mRNA expression levels of Bax and Bak. Incubation with GLP-1(7–36) amide for 24 h attenuated the RNA expression of miR-23a and increased the mRNA and protein expression of PGC-1α. Inhibition of miR-23a expression by cell transfection led to increases in the mRNA and protein expression of PGC-1α. In addition, the mRNA expression of UCP2 increased after incubation with GLP-1(7–36) for 24 h. In conclusion, GLP-1 induced increased expression of mitochondrial protective gene PGC-1α by downregulating miR-23a to inhibit hepatocyte apoptosis and also enhanced UCP2 to reduce apoptosis.

Effect of Phosphodiesterase Inhibitors on UCP1 Gene Expression in Brown Adipocytes

Brown adipose tissue (BAT) is a highly thermogenic organ and thermogenesis can be stimulated in cultured BAT with caffeine and RO 20-1724 in combination with a neurotransmitter norepinephrine (NE). Caffeine and RO 20-1724 are well known phoshphodiesterase inhibitors which stimulate UCP1 gene expression in BAT. Stimulation of BAT by 1 μM of caffeine and 0.25 mM of RO 20-1724 shows very little UCP1 mRNA expression and cyclic AMP (cAMP) production in comparison to 0.1 μM of NE. However, addition of NE in the presence of these compounds, the UCP1 mRNA expression and cAMP production increase significantly (becomes more than double) in comparison to the effect of NE alone. This study indicates that the thermogenic effect of NE may be increased significantly after inhibition of phosphodiesterase activity wit caffeine and RO 20-1724.

Differential effects of Roux-en-Y gastric bypass surgery on brown and beige adipose tissue thermogenesis

BackgroundThere are numerous reports of increased energy expenditure after Roux-en-Y gastric bypass (RYGB) surgery in humans and rodent models but the underlying mechanisms remain poorly understood. In the present study we assessed at the gene expression level whether RYGB leads to recruitment of brown adipose tissue (BAT) and/or beige adipose tissue (BeAT) as a means of enhanced facultative thermogenesis and increased energy expenditure after surgery. MethodsDiet-induced obese male Wistar rats were randomized into RYGB-operated (n=10), sham-operated ad libitum fed (Sham) (n=7) or sham-operated body weight matched (BWM) to RYGB groups (n=7). At a stage of postoperatively stabilized weight reduction, BAT (interscapular), subcutaneous (inguinal) and visceral (epididymal and perirenal) white adipose tissue (WAT) depots were collected in the fasted state. Expression of thermoregulatory genes (UCP1, CIDEA and PRDM16) in BAT and WAT as well as specific markers of BeAT (Ear2 and TMEM26) in WAT was analyzed using RT-qPCR. ResultsCompared to Sham rats, UCP1 mRNA expression in BAT was significantly reduced in BWM, but not in RYGB rats. No differences in mRNA expression were found for thermoregulatory proteins or for markers of BeAT in subcutaneous or visceral WAT depots between RYGB and Sham groups. ConclusionThe compensatory decrease in BAT thermogenic gene expression typically associated with body weight loss is attenuated after RYGB which, as opposed to recruitment of BeAT, may contribute to overall increases in energy expenditure and weight loss maintenance after surgery.

Differences in mitochondrial DNA inheritance and function align with body conformation in genetically lean and fat sheep.

Body weight and adiposity are determined by the balance between energy intake, energy expenditure, and nutrient deposition. We have identified differences in appetite-regulating peptides in sheep selectively bred to be either lean or fat, wherein gene expression for orexin and melanin-concentrating hormone are elevated in the lean group. Despite this, the underlying mechanisms leading to differences in body composition in the lean and fat lines remains unknown. We measured postprandial temperature in adipose tissue and muscle to ascertain whether a difference in thermogenesis is associated with the difference in body composition in genetically lean (n = 8) and fat (n = 12) ewes. Body weight was higher (P < 0.01) but percent fat mass was lower (P < 0.001) in the lean group. The percent lean mass was similar in lean and fat groups. Animals received intracerebroventricular cannulae and temperature probes implanted into the retroperitoneal fat and the hind-limb skeletal muscle (vastus lateralis). Animals were meal fed (1100-1600 h) to entrain postprandial thermogenesis. Food intake was similar between lean and fat animals. Postprandial thermogenesis was greater (P < 0.05) in the retroperitoneal adipose tissue of lean animals but not in skeletal muscle. Intracerebroventricular infusion of leptin reduced (P< 0.05) food intake by an equal extent in both groups. Postprandial expression of UCP1 mRNA was greater (P < 0.05) in retroperitoneal fat of lean animals, with similar UCP3 expression in skeletal muscle. Mitochondrial genome sequencing indicated haplotypic clustering in lean and fat animals within both the encoding and nonencoding regions. This demonstrates that differences in body composition may be underpinned by differences in thermogenesis, specifically within adipose tissue. Furthermore, thermogenic differences may be associated with specific mitochondrial DNA haplotypes, suggesting a strong genetic component inherited through the maternal lineage.

Effect of Mouse Strain on Dietary CLA and Coconut Oil‐Induced Lipolysis

Dietary conjugated linoleic acid (CLA)‐induced lipolysis and body fat loss are enhanced in mice fed coconut oil (CO); however, differences between mouse strains have been observed. This study was designed to evaluate the response to CLA and oil source in 4 common mouse strains. Male CF‐1, ICR, NIH, and Swiss Webster mice (3‐wk‐old, n = 24 per strain) were fed diets containing either soy oil (SO) or CO for 6 weeks, followed by 0 or 0.5% CLA (replacing base oil w/w) for 12 days. Tissue weights were measured for the calculation of a body fat index (BFI): epididymal + retroperitoneal fat pads/body weight*100. Epididymal and retroperitoneal fat pads were pooled and used for ex vivo lipolysis analysis and real time RT‐PCR. We detected an oil*CLA interaction (P = 0.03) on BFI where SO‐fed mice were the fattest and CO+CLA‐fed mice were the leanest, and a main effect of strain (P &lt; 0.001) where Swiss Webster mice were the fattest and NIH mice the leanest, but no diet by strain interactions. Lipolysis was stimulated by both CO (P &lt; 0.001) and CLA (P = 0.002) with no effect of strain. No differences in the mRNA expressions of UCP1, UCP2, UCP3, or CPT1 were detected but UCP1 expression was positively correlated (r = 0.26, P = 0.01) with lipolysis. As expected, the BFI was negatively correlated (r = ‐0.43, P &lt; 0.001) with lipolysis but positively correlated (r = 0.35, P = 0.001) with serum NEFA. In conclusion, we found that mouse strain does not significantly impact the response to CLA and/or CO and no evidence of increased UCP expression in the adipose tissue of CLA‐fed mice.

TRB3 Inhibits Brown Adipocyte Differentiation and Function by Suppressing Insulin Signaling

Recent studies have demonstrated that adult humans have substantial amounts of functioning brown adipose tissue (BAT), the activity of which inversely correlates with obesity and type 2 diabetes. Since BAT has been implicated as an anti‐obese and anti‐diabetic tissue, it is important to understand the signaling molecules that regulate BAT function. Our hypotheses were that TRB3 mediates obesity‐ and diabetes‐induced impairments in BAT differentiation and function, and that inhibition of TRB3 improves BAT function. Here, we report that TRB3 expression in BAT of high‐fat fed mice and ob/ob mice was significantly increased by 56% and 110%; and this coincided with 56% and 58% decreases in the expression of BAT specific uncoupling protein 1, UCP1. Overexpression of TRB3 in brown preadipocytes significantly impaired cell differentiation as assessed by Oil‐Red O staining and expression of genes involved in BAT differentiation and function (UCP1: 73%; PRDM16: 32%; PPARγ: 25%). Consistent with these findings, TRB3KO mice exhibited higher UCP1 mRNA (80%) and protein (780%) expression in BAT, and were cold resistance (rectal temperature at 4oC for 2hrs; WT: 34.3oC ± 0.4 vs. 35.7oC ± 0.1). Based on previous studies showing that deletion or pharmaceutical inhibition of insulin signaling impairs BAT differentiation and function, we assessed insulin signaling in brown preadipocytes and BAT in vivo. Overexpression of TRB3 in cells impaired insulin‐stimulated IRS1 Y612 (38%) and Akt S473 (45%) phosphorylation, whereas TRB3KO mice displayed improved IRS1 Y612 (70%) and Akt S473 (135%) phosphorylation. These data demonstrate that TRB3 regulates BAT differentiation and function presumably by insulin signaling regulation.

IL15 Promotes Myogenic and Brown Adipose Tissue Associated Genes while Decreasing AMPK Activation in C2C12 Skeletal Muscle Cells

Skeletal muscle (SKM) has come to the forefront as an endocrine regulator of obesity due to its ability to secrete myokines into circulation. Many myokines, in particular IL15, have been shown to increase in circulation following exercise. IL15 may act to decrease fat mass while increasing lean mass and possibly increase brown adipose tissue (BAT). Little is known about the molecular mediators of IL15 following exercise. We have previously shown that AMPK acts upstream of IL15 expression but data are conflicting. Here we aimed to determine the effects of IL15 on genes associated with myogenesis, BAT, and AMPK activation. Differentiated C2C12 SKM cells were stimulated for 24 hrs with 100 or 1000 ng/ml of IL15. Cells were harvested and mRNA was measured for myogenic markers Myf5, MCK, mitochondrial uncoupling protein UCP2, and genes highly expressed in BAT CIDEA and ELOVL. Additionally, phosphorylation (p) of AMPK at Thr172 was assessed by western blotting. IL15 stimulated increases (P<0.05) in Myf5, MCK, UCP2, and CIDEA mRNA expression exclusively with 100 ng/ml. Significant elevations in ELOVL mRNA expression were only observed with 1000 ng/ml of IL15 treatment (P<0.05). C2C12 cells treated with both doses of IL15 decreased pAMPK. Our data indicate that IL15 is involved in promoting myogenic, mitochondrial uncoupling, and BAT associated gene expression. Further it appears that IL15 paradoxically decreases activation of AMPK in C2C12 cells. Further studies aimed at elucidating the role of IL15 in mediating SKM metabolism, in particular myogenesis and BAT, are warranted, thus providing potential therapies for the treatment of obesity.

A platelet-activating factor (PAF) receptor deficiency exacerbates diet-induced obesity but PAF/PAF receptor signaling does not contribute to the development of obesity-induced chronic inflammation

Platelet-activating factor (PAF) is a well-known phospholipid that mediates acute inflammatory responses. In the present study, we investigated whether PAF/PAF receptor signaling contributed to chronic inflammation in the white adipose tissue (WAT) of PAF receptor-knockout (PAFR-KO) mice. Body and epididymal WAT weights were higher in PAFR-KO mice fed a high-fat diet (HFD) than in wild-type (WT) mice. TNF-α mRNA expression levels in epididymal WAT and the infiltration of CD11c-positive macrophages into epididymal WAT, which led to chronic inflammation, were also elevated in HFD-fed PAFR-KO mice. HFD-fed PAFR-KO mice had higher levels of fasting serum glucose than HFD-fed WT mice as well as impaired glucose tolerance. Although PAF receptor signaling up-regulated the expression of TNF-α and lipopolysaccharide induced the expression of acyl-CoA:lysophosphatidylcholine acyltransferase 2 (LPCAT2) mRNA in bone marrow-derived macrophages, no significant differences were observed in the expression of LPCAT2 mRNA and PAF levels in epididymal WAT between HFD-fed mice and normal diet-fed mice. In addition to our previous finding in which energy expenditure in PAF receptor (PAFR)-deficient mice was low due to impaired brown adipose tissue function, the present study demonstrated that PAF/PAF receptor signaling up-regulated the expression of Ucp1 mRNA, which is essential for cellular thermogenesis, in 3T3-L1 adipocytes. We concluded that the marked accumulation of abdominal fat due to HFD feeding led to more severe chronic inflammation in WAT, which is associated with glucose metabolism disorders, in PAFR-KO mice than in WT mice, and PAF/PAF receptor signaling may regulate energy expenditure and adiposity.

RNA-seq analysis of the rat placentation site reveals maternal obesity-associated changes in placental and offspring thyroid hormone signaling

IntroductionIn animal models, maternal obesity (OB) leads to augmented risk of offspring OB. While placental function is influenced by maternal habitus, the effect of maternal obesity on the interacting zones of the placenta [the labyrinth (LZ), junctional (JZ) and metrial gland (MG)] remains unknown. MethodsUsing a rat maternal obesity model, we conducted transcriptomic profiling of the utero-placental compartments and fetal liver (FL) at dpc 18.5, in conjunction with analyses of mRNA expression of key thyroid hormone (TH) signaling genes in the placenta, fetus and weanling offspring. Results and DiscussionGene expression analysis of placenta and offspring revealed that each utero-placental compartment responds distinctly to maternal OB with changes in inflammatory signaling, lipid metabolism and hormone stimulus being the predominant effects. OB-induced alterations in 17 genes were confirmed by qPCR, including reductions in thyrotropin-releasing hormone (Trh) in JZ. We further characterized mRNA and protein expression of TH signaling regulators including deiodinases (Dio), TH receptors (Tr), and downstream targets (uncoupling proteins (Ucp)). A concerted down-regulation of multiple facets of thyroid hormone signaling in the JZ and FL was observed. JZ expression of thyroid hormone signaling components Trh, Dio2, Trα, and Ucp2 were negatively associated with maternal leptin. mRNA expression of TRH, TRβ and UCP1 were also decreased in term placenta from OB women. Finally, our studies identified persistent impairments in expression of TH related genes in tissues from offspring of obese dams. ConclusionsThe role of lower placental thyroid expression is worthy of further study as a possible pathway that leads to low energy metabolism and obesity in animals born to obese mothers.

Abstract 4325: Overexpression of UCP2 is associated with tumor progression in Iranian breast cancer patients

Abstract Introduction: Uncoupling proteins (UCPs) are a family of inner mitochondrial membrane proteins whose function is to allow the re-entry of protons to the mitochondrial matrix, to decrease membrane potential and production of reactive oxygen species (ROS). Due to their pivotal role in the intersection between energy efficiency and oxidative stress, UCPs are being investigated for a potential role in cancer researches .UCP2 proteins functions in a variety of cell types as a sensor of mitochondrial oxidative stress and may be activated by superoxide or subsequently formed lipid peroxidation products. The ability of cancer cells to regulate ROS levels contributes greatly to autonomous growth, the evasion of apoptosis, and other hallmark characteristics of adaptation. Thus, UCP2 activity, a negative regulator of ROS, should be related to cancer development or progression. Over expression of UCP2 has been shown in different cancers. However, until now the role of UCP2 in breast cancers is not well understood. The aim of the current research study was to evaluate the association of UCP2 expression and clinic-pathological features in Iranian breast cancer patients. Patients and Methods: Thirty five breast cancer patients who referred to the National Cancer Institute (NCI) at Imam Khomeini Hospital Complex, Tehran, Iran from Oct. 2007 to Oct. 2009 were contributed in this study. The pathologic changes in tumor samples were determined by two expert pathologists. Each specimen was immediately frozen following resection and stored at -80°C until subjected to RNA extraction. UCP2 expression was analyzed by relative PCR method was performed in subjects. Results and Conclusion: The expression of UCP2 mRNA in 31 out of 35 breast cancer tissue samples and its adjacent tissue samples was determined. The expression level of UCP2 mRNA was about four-fold higher in 58% of breast cancer tissue samples than its adjacent tissue samples. The correlation between UCP2 expression and clinical pathological features of breast cancer including tumor stage, histological grade, estrogen receptor status, progesterone receptor status, Her-2/neu status, lymph node status, P53 status and metastasis status were analyzed. There was not a significant association between expression levels of UCP2 and clinical pathological features (P&amp;gt; 0.05). However, there was a significant association between the UCP2 expression and tumor size (P&amp;lt; 0.028). This finding may significantly play a role in the etiology of tumor development of breast cancer. Furthermore, our finding may be lead to determine whether UCP2 expression is an effective factor for tumor development in breast cancer cells so, targeted therapy drugs to impact this gene expression in the nucleus may be useful. Further studies are warranted to confirm these findings. Note: This abstract was not presented at the meeting. Citation Format: Neda Maraghechi, Massoud Ghaffarpour, Golna Asaadi Tehrani. Overexpression of UCP2 is associated with tumor progression in Iranian breast cancer patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4325. doi:10.1158/1538-7445.AM2014-4325

Glucagon is essential for adaptive thermogenesis in brown adipose tissue.

Glucagon, a counterregulatory hormone to insulin, serves as a regulator of glucose homeostasis and acts in response to hypoglycemia. Earlier studies have shown that glucagon administration induces thermogenesis in experimental animal models. However, it is not known whether endogenous glucagon is involved in the regulation of brown adipose tissue (BAT) function. Here we investigated the role of glucagon in cold-induced thermogenesis in male mice deficient in proglucagon-derived peptides (GCGKO mice). Upon exposure to cold, GCGKO mice exhibited a greater decrease in rectal temperature than control mice. The cold exposure-induced increase in oxygen consumption in GCGKO mice was less than that seen in control mice. Moreover, the increase in oxygen consumption after administration of a β3-adrenergic receptor agonist, CL-316,243, was also lesser in GCGKO than in control mice. Expression of thermogenic genes, including the gene encoding uncoupling protein 1 (Ucp1), was reduced in the BAT of GCGKO mice under ambient as well as cold conditions. Administration of glucagon restored the expression of Ucp1 mRNA in the BAT as well as the expression of the fibroblast growth factor 21 gene (Fgf21) in the liver. Supplementation with glucagon for 2 weeks resulted in higher plasma Fgf21 levels and improved responses to CL-316,243 in GCGKO mice. These results indicated that endogenous glucagon is essential for adaptive thermogenesis and that it regulates BAT function, most likely by increasing hepatic Fgf21 production.