UCP2 Gene Expression Research Articles

1647-P: Novel Functions of CXCL12 as a Brown Adipocyte–Derived Secreted Factor

The capacity of brown adipose tissue (BAT) to regulate metabolism through cold-induced thermogenesis and secretion of molecules appeals as a potential therapeutic against metabolic disease. BAT secreted factors have gained interest as they may coordinate the adaptive response to cold and tissue remodeling. Yet, BAT secretory functions need deeper investigation before identifying druggable candidates. Thus, our group aimed to study secreted factors from active brown adipocytes that may sway adipocyte function and/or may orchestrate inter-cellular communications. For this, mRNA levels in mature adipocytes of brown, beige and white adipose depots from mice exposed to 21 days of cold were evaluated using RNA sequencing, and bioinformatic analysis was used to filter for potentially secreted factors. Cxcl12 was found to be the most cold-induced chemokine specifically in BAT. mRNA expression analysis of Cxcl12 by qPCR and fluorescence in-situ hybridization revealed its enrichment in brown adipocytes upon cold. Cold also increased CXCL12 levels in BAT media but not plasma, indicating a potential local action. Cxcl12 knockdown in active brown adipocytes impaired thermogenesis, estimated by Ucp1 gene expression, norepinephrine-induced lipolysis and mitochondrial respiration, despite intact β-adrenergic signaling, as estimated by immunoblotting of phosphorylated proteins. Together, these data suggest that Cxcl12 regulates adipocyte function independently from the β-adrenergic pathway. Additionally, CXCL12 exerted inter-cellular crosstalks by promoting macrophage chemotaxis and neurite outgrowth in vitro. Here we present CXCL12 as a novel brown adipocyte, cold-induced secreted factor involved in adipocyte function and inter-cellular crosstalk within BAT. Further characterization of the role of CXCL12 and other secreted factors in BAT will provide valuable knowledge on the adaptive mechanisms of BAT to cold and may open new avenues to leverage BAT functions for the treatment of metabolic disease. Disclosure M.Agueda oyarzabal: None. M.Tozzi: None. T.W.Schwartz: None. C.C.Schéele: Research Support; Novo Nordisk A/S. B.Emanuelli: None. K.Plucinska: None. M.Isidor: None. L.R.Ingerslev: None. P.Petersen: None. O.Dmytriyeva: None. J.Henningsen: None. E.Brown: None. K.Rupar: None. Funding Novo Nordisk Foundation (18CC0034900, 19SA0035436); Copenhagen Bioscience PhD Program

Salt-inducible kinase inhibition promotes the adipocyte thermogenic program and adipose tissue browning

ObjectiveNorepinephrine stimulates the adipose tissue thermogenic program through a β-adrenergic receptor (βAR)–cyclic adenosine monophosphate (cAMP)–protein kinase A (PKA) signaling cascade. We discovered that a noncanonical activation of the mechanistic target of rapamycin complex 1 (mTORC1) by PKA is required for the βAR-stimulation of adipose tissue browning. However, the downstream events triggered by PKA-phosphorylated mTORC1 activation that drive this thermogenic response are not well understood. MethodsWe used a proteomic approach of Stable Isotope Labeling by/with Amino acids in Cell culture (SILAC) to characterize the global protein phosphorylation profile in brown adipocytes treated with the βAR agonist. We identified salt-inducible kinase 3 (SIK3) as a candidate mTORC1 substrate and further tested the effect of SIK3 deficiency or SIK inhibition on the thermogenic gene expression program in brown adipocytes and in mouse adipose tissue. ResultsSIK3 interacts with RAPTOR, the defining component of the mTORC1 complex, and is phosphorylated at Ser884 in a rapamycin-sensitive manner. Pharmacological SIK inhibition by a pan-SIK inhibitor (HG-9-91-01) in brown adipocytes increases basal Ucp1 gene expression and restores its expression upon blockade of either mTORC1 or PKA. Short-hairpin RNA (shRNA) knockdown of Sik3 augments, while overexpression of SIK3 suppresses, Ucp1 gene expression in brown adipocytes. The regulatory PKA phosphorylation domain of SIK3 is essential for its inhibition. CRISPR-mediated Sik3 deletion in brown adipocytes increases type IIa histone deacetylase (HDAC) activity and enhances the expression of genes involved in thermogenesis such as Ucp1, Pgc1α, and mitochondrial OXPHOS complex protein. We further show that HDAC4 interacts with PGC1α after βAR stimulation and reduces lysine acetylation in PGC1α. Finally, a SIK inhibitor well-tolerated in vivo (YKL-05-099) can stimulate the expression of thermogenesis-related genes and browning of mouse subcutaneous adipose tissue. ConclusionsTaken together, our data reveal that SIK3, with the possible contribution of other SIKs, functions as a phosphorylation switch for β-adrenergic activation to drive the adipose tissue thermogenic program and indicates that more work to understand the role of the SIKs is warranted. Our findings also suggest that maneuvers targeting SIKs could be beneficial for obesity and related cardiometabolic disease.

Fenofibrate mildly stimulates browning-associated expression in white adipose tissues of young but not old male rats.

The aim of this study was to examine the effects of the hypolipemic drug fenofibrate (FF) and aging on the expression of factors/enzymes involved in brown adipose tissue (BAT) function and browning of white adipose tissue epididymal (eWAT) and subcutaneous (sWAT) depots. Young-adult and old male Wistar rats were fed standard chow (control) or supplemented with 0.1% or 0.5% FF for 30 days. Tissue samples were analysed for gene expression and protein content, and stained with Oil Red O or hematoxylin and eosin. In BAT of young rats, 0.5% FF increased only Cbp/p300 interacting transactivator with Glu/Asp rich carboxy-terminal domain 1 (CITED1) protein content and Fgf21 and Gpr109A mRNA expression. The expression of oxidative metabolism related genes (Pgc1α, Cpt1b, Mcad) decreased after 0.5% FF. In BAT of old rats, FF did not affect UCP1 and CITED1 content and had little effect on gene expression. Oil Red O staining of BAT revealed no changes in lipid droplet area upon treatment in either age group. In eWAT of young rats, 0.1FF elevated UCP1 protein content and Ucp1, Pgc-1α, and Mcad expression, whereas 0.5% FF increased PPARα content and Pgc-1α, Cpt1b, Mcad, and Gpr109A levels. In eWAT of old rats, only 0.1FF increased Pgc1α and Mcad expression. In both age groups median cell area of eWAT adipocytes was reduced after 0.5% FF. In sWAT Ucp1 gene expression was very low and UCP1 protein was undetectable. FF upregulated Ucp1, Cited1, Eva1, and Cpt1b expression in sWAT of young rats, with diminished effects in old rats. In both age groups 0.5% FF increased Fgf21 expression in sWAT. Median cell area of sWAT adipocytes decreased only in young rats treated with 0.5% FF. Our results reveal that fenofibrate differentially affects gene expression in BAT, with diminished effects in old compared to young rats. In WAT of young rats FF modestly stimulates the expression of factors/enzymes involved in lipid oxidative metabolism and browning. Aging reduces both these effects. Gpr109A may present a novel gene target upregulated by FF in BAT and eWAT.

Thallium exposure interfered with heart development in embryonic zebrafish (Danio rerio): From phenotype to genotype

Thallium (Tl) is a rare trace metal element but increasingly detected in wastewater produced by coal-burning, smelting, and more recently, high-tech manufacturing industries. However, the adverse effects of Tl, especially cardiotoxicity, on aquatic biota remain unclear. In this study, zebrafish model was used to elucidate the effects and mechanisms of Tl(I) cardiotoxicity in developing embryos. Exposure of embryonic zebrafish to low-dose Tl(I) (25–100 μg/L) decreased heart rate and blood flow activity, and subsequently impaired swim bladder inflation and locomotive behavior of larvae. Following high-level Tl(I) administration (200–800 μg/L), embryonic zebrafish exhibited pericardial edema, incorrect heart looping, and thinner myocardial layer. Based on RNA-sequencing, Tl(I) altered pathways responsible for protein folding and transmembrane transport, as well as negative regulation of heart rate and cardiac jelly development. The gene expression of nppa, nppb, ucp1, and ucp3, biomarkers of cardiac damage, were significantly upregulated by Tl(I). Our findings demonstrate that Tl(I) at environmentally relevant concentrations interfered with cardiac development with respect to anatomy, function, and transcriptomic alterations. The cardiotoxic mechanisms of Tl(I) provide valuable information in the assessment of Tl-related ecological risk in freshwater environment.

Effect of oral cannabis administration on the fat depots of obese and streptozotocin-induced diabetic rats.

The prevalence of obesity and insulin-resistance is on the rise, globally. Cannabis have been shown to have anti-diabetic/obesity properties, however, the effect mediated at various fat depots remains to be clarified. The aim of this study was to (1) investigate the anti-diabetic property of an oral cannabis administration in an obese and streptozotocin-induced diabetic rat model and (2) to determine and compare the effect mediated at the peritoneal and intramuscular fat level. Cannabis concentration of 1.25 mg/kg body weight (relative to THC content) was effective in reversing insulin-resistance in the rat model, unlike the other higher cannabinoid concentrations. At the peritoneal fat level, gene expression of fat beigeing markers, namely Cidea and UCP1, weresignificantly increased compared to the untreated control. At the intramuscular fat level, on the other hand, CE1.25 treatment did not promote fat beigeing but instead significantly increased mitochondrial activity, relative to the untreated control. Therefore, these findings indicate that the mechanism of action of oral cannabis administration, where glucose and lipid homeostasis is restored, is not only dependent on the dosage but also on the type of fat depot investigated.

Integrate metabolomics strategy and target prediction to reveal the ameliorate effect of four typical ‘cold’ property herbs on hyperthyroidism rats

Ethnopharmacological relevanceThe ‘cold’ property herbs are commonly applied in heat syndrome. Unfortunately, the underlying mechanisms of the ‘cold’ property herbs on heat syndrome has not been investigated. Aim of the studyThe study aimed to probe the activities of the four typical ‘cold’ property herbs on hyperthyroidism. Materials and methodsFirstly, the four typical ‘heat’ property herbs were set as contrasting experiment. Then. the physical sign, thyroid function and metabolism profile (multivariate statistical analysis) were assessing the difference between the four typical ‘cod’ property herbs and the four typical ‘heat’ property herbs. H&E staining were used to confirmed the influence of the typical ‘cold’ property herbs on hyperthyroidism. A metabolomics approach combine with network pharmacology were explored the effected mechanism of the typical ‘cold’ property herbs on hyperthyroidism. the gene expression of UCP-1 was detected by RT-PCR. The metabolites pathway and target-associated metabolites were verified Na+/K+-ATP enzyme and GSH, as well IL6, IL17, MAPK and PPAR-γ, which detected by commercial kits and Western blot. ResultsIt is proved that the four typical ‘cold’ property herbs effectively ameliorate the physical sign, thyroid function and metabolism profile in hyperthyroidism rats, but the four typical ‘heat’ property herbs showed no benefit. Moreover, the four typical ‘cold’ property herbs regulated energy metabolism, glutathione metabolism, taurine hypotaurine metabolism, thyroid hormone synthesis, arachidonic acid metabolism and linoleic acid metabolism and the inflammation mediated by inflammatory factor (IL6, IL17), Ca2+ and MAPK signaling pathway. And the levels of UCP-1, Na+/K+-ATP enzyme, GSH, and the targets protein of IL6, IL17, MAPK and PPAR-γ were ameliorated by the four typical ‘cold’ property herbs. ConclusionThe four typical ‘cold’ property herbs could alleviate hyperthyroidism by ameliorate thyroid hormone synthesis, restraining inflammation and oxidative stress via regulating energy metabolism, glutathione metabolism, taurine hypotaurine metabolism, arachidonic acid metabolism and linoleic acid metabolism and Ca 2+/MAPK signaling pathway, which might be a useful strategy for treating hyperthyroidism.

MYPT1-PP1β phosphatase negatively regulates both chromatin landscape and co-activator recruitment for beige adipogenesis

Protein kinase A promotes beige adipogenesis downstream from β-adrenergic receptor signaling by phosphorylating proteins, including histone H3 lysine 9 (H3K9) demethylase JMJD1A. To ensure homeostasis, this process needs to be reversible however, this step is not well understood. We show that myosin phosphatase target subunit 1- protein phosphatase 1β (MYPT1-PP1β) phosphatase activity is inhibited via PKA-dependent phosphorylation, which increases phosphorylated JMJD1A and beige adipogenesis. Mechanistically, MYPT1-PP1β depletion results in JMJD1A-mediated H3K9 demethylation and activation of the Ucp1 enhancer/promoter regions. Interestingly, MYPT1-PP1β also dephosphorylates myosin light chain which regulates actomyosin tension-mediated activation of YAP/TAZ which directly stimulates Ucp1 gene expression. Pre-adipocyte specific Mypt1 deficiency increases cold tolerance with higher Ucp1 levels in subcutaneous white adipose tissues compared to control mice, confirming this regulatory mechanism in vivo. Thus, we have uncovered regulatory cross-talk involved in beige adipogenesis that coordinates epigenetic regulation with direct activation of the mechano-sensitive YAP/TAZ transcriptional co-activators.

Mechanisms Underlying the Protective Effect of Maternal Zinc (ZnSO4 or Zn-Gly) against Heat Stress-Induced Oxidative Stress in Chicken Embryo.

Environmental factors such as high temperature can cause oxidative stress and negatively affect the physiological status and meat quality of broiler chickens. The study was conducted to evaluate the effects of dietary maternal Zn-Gly or ZnSO4 supplementation on embryo mortality, hepatocellular mitochondrial morphology, liver antioxidant capacity and the expression of related genes involved in liver oxidative mechanisms in heat-stressed broilers. A total of 300 36-week-old Lingnan Yellow broiler breeders were randomly divided into three treatments: (1) control (basal diet, 24 mg zinc/kg); (2) inorganic ZnSO4 group (basal diet +80 mg ZnSO4/kg); (3) organic Zn-Gly group (basal diet +80 mg Zn-Gly/kg). The results show that maternal zinc alleviated heat stress-induced chicken embryo hepatocytes’ oxidative stress by decreasing the content of ROS, MDA, PC, 8-OHdG, and levels of HSP70, while enhancing T-SOD, T-AOC, CuZn-SOD, GSH-Px, CTA activities and the content of MT. Maternal zinc alleviated oxidative stress-induced mitochondrial damage in chick embryo hepatocytes by increasing mitochondrial membrane potential and UCP gene expression; and Caspase-3-mediated apoptosis was alleviated by increasing CuZn-SOD and MT gene expression and decreasing Bax gene expression and reducing the activity of caspase 3. Furthermore, maternal zinc treatment significantly increased Nrf2 gene expression. The results above suggest that maternal zinc can activate the Nrf2 signaling pathway in developing chick embryos, enhance its antioxidant function and reduce the apoptosis-effecting enzyme caspase-3 activities, thereby slowing oxidative stress injury and tissue cell apoptosis.

Improved oral nutraceutical-based intervention for themanagement of obesity: pterostilbene-loaded chitosan nanoparticles.

Aim: To formulate and assess the oral anti-obesity effect of polymeric-based pterostilbene (PS)-loaded nanoparticles. Methods: Pterostilbene-hydroxypropyl β-cyclodextrin inclusion complex loaded in chitosan nanoparticles (PS/HPβCD-NPs) were prepared and characterized in vitro. Cytotoxicity, pharmacokinetics and anti-obesity effects were assessed on Caco-2 cell line and high-fat-diet-induced obesity rat model, respectively. In vivo assessment included histological examination, protein and gene expression of obesity biomarkers in adipose tissues. Results: Safe PS/HPβCD-NPs were successfully prepared with improved bioavailability compared with free PS. PS/HPβCD-NPs showed an improved anti-obesity effect, as supported by histological examination, lipid profile, UCP1 gene expression and protein expression of SIRT1, COX2, IL-6 and leptin. Conclusion: Orally administered PS nanoparticles represent a new and promising anti-obesity strategy owing to the sustainable weight loss and minimal side effects; this may be of great socio-economic impact.

Berberine chloride (dual topoisomerase I and II inhibitor) modulate mitochondrial uncoupling protein (UCP1) in molecular docking and dynamic with in-vitro cytotoxic and mitochondrial ATP production

Obesity initiates numerous diseases like cardiovascular, metabolic, and type 2 diabetes, and obesity is a vital cause of death worldwide. Plants are necessary to the source of life. Several drug compounds isolated from plants are called phytochemicals which are safe, effective drug moieties to treat several diseases. Berberine chloride is a dual topoisomerase I and II inhibitor, that exhibited potent antitumor activities against several malignancies. However, the effect of Berberine on mitochondria remains unknown. The focus of this study was to determine the role of Berberine on mitochondrial uncoupling protein (UCP1), ATP production, and cytotoxic effect of HEK293T cell at a time and dose-dependent manner analysis by CCK8 assay. The upregulation of mitochondrial UCP1 gene expression reduces adipocyte content by initiating thermogenesis. In this study, berberine chloride significantly up-regulates UCP1 gene expression in brown adipocytes. AT 10 µM concentration of Berberine 48 h treatment demonstrated significant cell death. The decreased level of ATP production leads to mitochondrial uncoupling. Initiate thermogenesis reducing fat droplets in adipocytes. The first time, we used molecular docking and dynamic of Berberine with UCP1 gene in this study and revealed therapeutic potential of Berberine via modulation of mitochondrial UCP1 gene. Further investigation will reveal new insight into mechanisms to treat metabolic-related diseases. Communicated by Ramaswamy H. Sarma

Effects of Metformin and Quercetin on the Thermogenesis and Muscle Metabolism of Piglets

Metformin is usually used to treat type 2 diabetes, and it is also known to have beneficial effects on body weight and composition. However, the mechanism of its function has not been clarified yet. The aim of this study is to investigate the effects of metformin on the thermogenesis, muscle metabolism, and muscle fiber type of newborn piglets. Total 24 newborn piglets were randomly divided into 4 groups: control group (C, n=6) with no treatment until weaning; Metformin group (M, n=6) with 50mg/kg metformin until weaning; Quercetin group (Q, n=6) with 50mg/kg quercetin until weaning; Metformin + Quercetin group (MQ, n=6) with 50mg/kg metformin + 50mg/kg quercetin until weaning. During the weaning, the surface and rectal temperatures were recorded at 0, 1, 2, 4, 7, 14, 21d. After weaning, all the piglets were fed with the same nursery diet for 6 weeks. After 6 weeks of the nursery, all the piglets were slaughtered, and the longissimus dorsi muscle of each pig was collected to determine gene expression. The results showed that the surface temperature of C group was higher than M, Q, and MQ groups at day‐21 (P<0.01, Figure 1), and rectal temperatures of M, Q, and MQ groups were higher than C from day‐1 to day‐21 (P<0.05, Figure 2). The gene expression of UCP3 and SLN in the M group was higher than C and Q (P<0.05, Figure 3). The MyHC I expression of the MQ group was higher than the C group (P<0.05, Figure 3). The results indicate that feeding metformin and quercetin during weaning increased the rectal thermogenesis and impacted the gene expression related to muscle metabolism and muscle fiber type.

Coffee intake mitigated high fat diet‐induced whitening of brown adipose tissue in obese mice

The aim of this study was to evaluate the preventive and therapeutic effect of coffee consumption on metabolic and molecular aspects of adipose tissue (AT) remodeling in a high‐fat diet‐induced obesity mice. Our hypothesis is that coffee consumption mitigates brown adipose tissue (BAT) whitening and prevent obesity related comorbidities. 50 male mice of 90 days of the C57BL6 lineage divided into 3 groups: Control (C); High‐fat (HF) and prevention 1% w/w coffee (HF‐CP). After 10 weeks, the HF group gave rise to the treatment 1% w/w coffee group (HF‐CT), totaling 4 different groups for another 4 weeks, totaling 14 weeks of experiment. The HF‐CP group has lower body mass than the high fat (HF) group (‐8%, p < 0.05), better AT distribution, with smaller adipocytes and smaller mean sectional area (p<0.05). Both groups that received coffee associated with a high‐fat diet (HF‐CP and HF‐CT) improved glucose metabolism when compared to the HF group, the glucose tolerance test in the HF‐CP group was similar to the C. Coffee consumption prevented hyperinsulinemia and hyperleptinemia in the HF‐CP group, this group did not develop insulin resistance and in the group that consumed coffee after induction of obesity (HF‐CT) the hyperinsulinemia was attenuated. The plasma concentration of IL‐6 was reduced (p<0.05) in HF‐CP and HF‐CT when compared to the HF group. The immunofluorescence expression of UCP‐1was more intense in BAT of HF‐CP compared to others groups. Thermogenesis and mitochondrial biogenesis in BAT were higher with increased gene expression of UCP‐1, PPARγ, PRDM16, PCG1α, Rβ3A, OPA‐1in HF‐CP. Coffee has better effects when consumed preventively with better AT remodeling, with maintenance of the brown phenotype, thermogenic activity in BAT. Furthermore, coffee consumption was able to attenuate body mass gain, improve glucose and leptin homeostasis. When consumed after obesity induction, as a treatment, it was not as effective as prevention, however, there was also better BAT remodeling with attenuation of lightening, greater expression of thermogenic genes and reversal of hyperinsulinemia.

43 Mapping the Hypermetabolic Response in Burn Patients

IntroductionHypermetabolism, characterized by drastic increases in whole-body catabolism and resting energy expenditure (REE), is a hallmark response to a severe burn injury. This is believed to be driven in part by alterations in adipose tissue metabolism. We proposed to define the hypermetabolic response in adipose tissue from burn patients and create a roadmap of markers indicative of hypermetabolism to improve prognosis. We hypothesized that catabolic markers, such as uncoupling protein-1 (Ucp1) and growth differentiation factor-15 (Gdf15), would positively correlate with increasing days post-burn and REE.MethodsAdult burn patients (n=65) admitted to our burn center between 2011—2019 were included in this study. Subcutaneous white adipose tissues (sWAT) from the site of injury (n=85) and plasma were collected from severely burned patients ( ³20% total body surface area). Gene expression and circulating cytokine levels were measured by RT-qPCR and multiplex assays, respectively.ResultsWe found a significant correlation between increasing Ucp1 gene expression and days post-burn (p< 0.0001). Moreover, when samples were stratified into acute (1-3 days post-burn), moderate (4-9 days post-burn), and long-term ( >10 days post-burn) timepoints, a significant increase in Ucp1 gene expression was detected only in adipose tissues from long-term time points in comparison to non-burned control tissues (p< 0.01). However, we found that REE remained stagnant throughout hospital stay after a burn injury in our patient cohort. Thus, we did not detect a significant correlation between Ucp1 gene expression and REE. Further, while Gdf15 expression was most pronounced, albeit statistically insignificant, during the moderate timepoints, we did not detect any significant differences when correlated with days post-burn. Additionally, we determined that circulating levels of IL-6, IL-10, and monocyte chemoattractant protein-1 (MCP-1) were greatly elevated within the first seven days post-burn and gradually decreased over time, while vascular endothelial growth factor (VEGF) concentrations followed a similar pattern to Ucp1 gene expression.ConclusionsWhile Gdf15 expression may not accurately reflect catabolism in the adipose tissues of burn patients, Ucp1 gene expression may be used as a marker indicating a peak hypermetabolic period after ten days post-burn. This may also be reflected by circulating concentrations of VEGF. Moreover, IL-6, IL-10 and MCP-1 may be used as early determinants before the onset of hypermetabolism.

Adipocyte-specific Nos2 deletion improves insulin resistance and dyslipidemia through brown fat activation in diet-induced obese mice

ObjectiveInducible nitric oxide (NO) synthase (NOS2) is a well-documented inflammatory mediator of insulin resistance in obesity. NOS2 expression is induced in both adipocytes and macrophages within adipose tissue during high-fat (HF)-induced obesity. MethodsEight-week-old male mice with adipocyte selective deletion of the Nos2 gene (Nos2AD−KO) and their wildtype littermates (Nos2fl/fl) were subjected to chow or high-fat high-sucrose (HFHS) diet for 10 weeks followed by metabolic phenotyping and determination of brown adipose tissue (BAT) thermogenesis. The direct impact of NO on BAT mitochondrial respiration was also assessed in brown adipocytes. ResultsHFHS-fed Nos2AD−KO mice had improved insulin sensitivity as compared to Nos2fl/fl littermates. Nos2AD−KO mice were also protected from HF-induced dyslipidemia and exhibited increased energy expenditure compared with Nos2fl/fl mice. This was linked to the activation of BAT in HFHS-fed Nos2AD−KO mice as shown by increased Ucp1 and Ucp2 gene expression and augmented respiratory capacity of BAT mitochondria. Furthermore, mitochondrial respiration was inhibited by NO, or upon cytokine-induced NOS2 activation, but improved by NOS2 inhibition in brown adipocytes. ConclusionsThese results demonstrate the key role of adipocyte NOS2 in the development of obesity-linked insulin resistance and dyslipidemia, partly through NO-dependent inhibition of BAT mitochondrial bioenergetics.

Gene expression of glutathione S-transferase alpha, glutathione S-transferase rho, glutathione peroxidase, uncoupling protein 2, cytochrome P450 1A, heat shock protein 70 in liver of Oreochromis niloticus upon exposure of microcystin-LR, microcystin-RR and toxic cyanobacteria crude

ObjectiveMicrocystins (MCs) are considered to be one of the most hazard groups of cyanobacteria and are known as a group of cyclic polypeptide hepatotoxins of varying potency. The study determined the variation of gene expression of GSTA, GSTR, GPX, UCP2, CYP1A1 and HSP70 genes in liver of tilapia fish (Oreochromis niloticus) under the effect of MC-LR or MC-RR toxins. MethodsTilapia fish adult male fishes (n = 20; 120–178 g) obtained from fish farm. Fishes injected i.p. with a single dose of 50 μg/kg MC-LR, and 20 fishes injected with 500 μg/kg MC-RR. Whereas the control group was only received the vehicle solution. Total mRNA was isolated from 50 mg of hepatic sections. The relative levels of GSTA, GSTR, GPX, UCP2, HSP70/β actin mRNA were determined by RT-real time PCR. ResultsSignificantly increased in GSTA mRNA expression was observed in the liver of fish after exposure to all exposure groups. Variable alterations in the levels of GPx, GSTR, UCP2 and CYP1A mRNA expression were observed post exposure groups. Whereas, the relative level of HSP70 mRNA was increased at 12 h after MCs exposure and was elevated gradually at 24 h until 7 days post treatment. ConclusionThe presence of inducible expression of GSTA, GSTR and GPx, and no significant changes of CYP1A mRNA expression in the liver of tilapia post MCs exposure, indicates that it should be the phase II detoxification enzyme in the liver of tilapia, but not the phase I detoxification enzyme. In addition to restrain over production of ROS, increasing of UCP2 and HSP70 expression may play an important role as a molecular chaperone against oxidative stress consequently, preventing hepatic cells from apoptosis.

Irisin regulates thermogenesis and lipolysis in 3T3-L1 adipocytes

BackgroundAdipose tissue plays a pivotal role in the development and progression of the metabolic syndrome which along with its complications is an epidemic of the 21st century. Irisin is an adipo-myokine secreted mainly by skeletal muscle and targeting, among others, adipose tissue. In brown adipose tissue it upregulates uncoupling protein-1 (UCP1) which is responsible for mitochondrial non-shivering thermogenesis. MethodsHere we analyzed the effects of irisin on the metabolic activity of 3T3-L1 derived adipocytes through a mitochondrial flux assay. We also assessed the effects of irisin on the intracellular signaling through Western Blot. Finally, the gene expression of ucp1 and lipolytic genes was examined through RT-qPCR. ResultsIrisin affects mitochondrial respiration and lipolysis in a time-dependent manner through the regulation of PI3K-AKT pathway. Irisin also induces the expression of UCP1 and the regulation of NF-κB, and CREB and ERK pathways. ConclusionOur data supports the role of irisin in the induction of non-shivering thermogenesis, the regulation of energy expenditure and lipolysis in adipocytes. General significanceIrisin may be an attractive therapeutic target in the treatment of obesity and related metabolic disorders.

Retinoic acid promotes tissue vitamin A status and modulates adipose tissue metabolism of neonatal rats exposed to maternal high-fat diet-induced obesity.

Maternal obesity may compromise the micronutrient status of the offspring. Vitamin A (VA) is an essential micronutrient during neonatal development. Its active metabolite, retinoic acid (RA), is a key regulator of VA homeostasis, which also regulates adipose tissue (AT) development in obese adults. However, its role on VA status and AT metabolism in neonates was unknown and it was determined in the present study. Pregnant Sprague-Dawley rats were randomised to a normal fat diet (NFD) or a high fat diet (HFD). From postnatal day 5 (P5) to P20, half of the HFD pups received oral RA every 3 d (HFDRA group). NFD pups and the remaining HFD pups (HFD group) received placebo. Six hours after dosing on P8, P14 and P20, n 4 pups per group were euthanised for different measures. It was found that total retinol concentration in neonatal liver and lung was significantly lower in the HFD group than the NFD group, while the concentrations were significantly increased in the HFDRA group. The HFD group exhibited significantly higher body weight (BW) gain, AT mass, serum leptin and adiponectin, and gene expression of these adipokines in white adipose tissue compared with the NFD group; these measures were significantly reduced in the HFDRA group. BAT UCP2 and UCP3 gene expression were significantly higher in pups receiving RA. In conclusion, repeated RA treatment during the suckling period improved the tissue VA status of neonates exposed to maternal obesity. RA also exerted a regulatory effect on neonatal obesity development by reducing BW gain and adiposity and modulating AT metabolism.

Butein-Enriched Fractions of Butea monosperma (Lam.) Taub. Flower Decrease Weight Gains and Increase Energy Expenditure in High-Fat Diet-Induced Obese Mice.

Butea monosperma (Lam.) Taub. has been applied to treat inflammatory, metabolic, and infectious diseases. However, the antiobesity effects of B. monosperma (Lam.) Taub. flower (BMF) and the underlying mechanisms have not been determined. In this study, we analyzed the various extraction procedures, investigated the antiobesity effects, and identified the main chemical constituents of BMF. The BMF was subjected to acid hydrolysis in 5% H2SO4 in methanol at 50°C for 48 h and partitioned with ethyl acetate. The acid-hydrolyzed BMF ethyl acetate extracts (BMFE) strongly induced the expression of uncoupling protein 1 (Ucp1) and other thermogenic genes in C3H10T1/2 adipocytes. Daily oral administration of 70 mg/kg BMFE (BMFE70) to mice with diet-induced obesity resulted in less body weight gain, increased glucose tolerance, higher rectal temperature, and increased oxygen consumption. Qualitative and quantitative analyses along with treatments in Akt1 knockout mouse embryonic fibroblasts indicate that butein is a major active ingredient of BMFE, which stimulates Ucp1 gene expression. These data show the effects of butein-containing B. monosperma flower extract on thermogenesis and energy expenditure, further suggesting the potential role of BMFE as a functional ingredient in obesity and related metabolic diseases.

Adipose tissue expression of UCP1 and PRDM16 genes and their association with postprandial triglyceride metabolism and glucose intolerance

AimsUCP1 and PRDM16 genes, primarily involved in browning of adipose tissue that can affect lipid metabolism are also associated with diabetes risk. Therefore, we planned to study the adipose tissue expression of UCP1 and PRDM 16 genes in subjects with glucose intolerance to find out its association with postprandial triglyceride (PPTg) measures and T2DM. MethodsA total of 30 subjects were recruited in three groups i.e., NGT, prediabetes and T2DM (NDDM + known T2DM) who were matched for age, sex and BMI. An 8-hour standardized fat challenge test was performed to study lipemic responses. UCP1 and PRDM16 genes quantification in adipose tissue was performed by real-time PCR followed by SDS PAGE. ResultsUCP1 gene expression in SAT was significantly lower in T2DM and prediabetes as compared to NGT group while PRDM16 gene expression was significantly lower in T2DM group as compared to NGT group. UCP1 gene expression correlated with PPTg measures as well as with glycaemic measures while PRDM16 gene expression correlated with glycaemic measures only. ConclusionThis study found downregulation of PRDM16 and UCP1 gene expression in SAT in subjects with glucose intolerance. The association of UCP1 gene expression with PPTg dysmetabolism may contribute to greater predisposition to T2DM.

Maternal high fructose diet exacerbates white adipose tissue thermogenic process in offspring upon exposure to cold temperature

AimAn adverse endogenous environment during early life predisposes to metabolic disorder development. We previously reported adverse metabolic and adipose tissue effects in adult male rats born to dams fed with a fructose-rich diet (FRD). The aim of this work was to determine the effect of a FRD consumed by the pregnant mother on the white adipose tissue (WAT) browning capacity of male offspring at adulthood. Main methodsAdult SD male offspring from control (C) and FRD-fed mothers were exposed during one week to a cold stimulus. WAT browning capacity was studied through in vivo and in vitro approaches. Key findingsAfter cold exposure, WAT browning was higher in fructose-programmed animals as evidenced by an increase in ucp-1 gene expression, protein levels, and higher UCP-1 positive foci. Moreover, pgc1-α gene expression was increased. In vitro studies showed a lower adipogenic capacity in cells of prenatally fructose-exposed animals differentiated with a white differentiation cocktail, while a higher ucp-1 expression was noted when their cells were treated with a pro-beige differentiation cocktail. SignificanceFor the first time we demonstrate that pre-natal fructose exposure predisposes programmed male rats to a higher WAT browning-induced response, under stimulated conditions, despite an apparent lower basal thermogenic capacity. These results should be considered in future studies to generate new therapeutic approaches to deal with adverse programming malnutrition effects.