Changes in UCP mRNA expression levels in brown adipose tissue and skeletal muscle after feeding a high-energy diet and relationships with leptin, glucose and PPARgamma

Brown adipose tissue and skeletal muscle are known to be important sites for nonshivering thermogenesis. In this context, it is accepted that uncoupling proteins (UCPs) are involved in such process, but little is known about the physiological regulation of these proteins as affected by the intake of a high-energy (cafeteria) diet inducing fat deposition. In this study, the UCP messenger RNA (mRNA) expression in interscapular brown adipose tissue (iBAT) and skeletal muscle was assessed to evaluate the influence of a dietary manipulation on energy homeostasis regulation. We report a statistically significant increase in mRNA levels of iBAT UCP1 and UCP3 and a statistical marginal rise in skeletal muscle UCP3 mRNA expression after feeding a high-energy diet, whereas no changes in UCP2 expression were found in either tissue. Furthermore, significant positive associations between iBAT UCP1 and UCP3 mRNA levels with serum leptin were found. Although the expression of the b3 adrenoceptor (b3AR) was about 50% in the lean controls compared with the obese group in iBAT, no statistically significant changes were observed concerning peroxisome proliferator-activated receptor g2 (PPARg2) mRNA levels in muscle or iBAT. We conclude that feeding a diet inducing weight and fat gain produces different outcomes on iBAT and skeletal muscle UCP mRNA expression, revealing a tissue-dependent response for the three UCPs. Results suggest that the regulation of UCP expression in both tissues under these specific dietary conditions may be related to leptin circulating levels

Up-regulation of a thermogenesis-related gene (UCP1) and down-regulation of PPARgamma and aP2 genes in adipose tissue: possible features of the antiobesity effects of a beta3-adrenergic agonist.

A number of experiments have demonstrated the antiobesity effects of beta(3)-adrenergic receptor stimulation by promoting thermogenesis and/or lipolysis. While many studies have been performed in order to develop beta(3)-adrenergic agonists as a novel strategy in the management of obesity, more information is needed about the mechanisms involved in thermogenesis and the actions of these drugs on adipocyte differentiation. To address this, the possible thermogenic and antiadipogenic properties of Tertatolol, a beta(3)-adrenergic agonist, in a diet-induced obesity model has been tested. Animals fed on a high-fat diet gained more weight and fat mass as compared with control and high-fat fed animals treated with Tertatolol. A RT-PCR was carried out in white adipose tissue specific genes involved in thermogenesis such as uncoupling proteins (UCPs) and adipogenesis such as peroxisome proliferator-activated receptor (PPARgamma2), retinoid receptors (RXRalpha/RARalpha), and fatty acid binding protein (aP2). Levels of UCP1 mRNA were augmented in the Tertatolol-treated group as compared to non-treated high-fat fed animals, while the beta(3)-adrenergic agonist treatment significantly decreased the expression levels of aP2 and transcription factors such as PPARgamma2 and the ratio RXRalpha/RARalpha as compared to obese rats. Altogether these data suggest that the antiobesity effects of beta(3)-adrenergic agonists are not limited to the promotion of thermogenesis and/or lipolysis and support the implication that these beta(3)-adrenergic agonists also affect fat deposition by impairing adipogenesis in white adipose tissue (WAT)

Differential expression of oxidative stress and inflammation related genes in peripheral blood mononuclear cells in response to a low-calorie diet: a nutrigenomics study

Nutrigenomics is a new application of omics technologies in nutritional science. Nutrigenomics aims to identify molecular markers of diet-related diseases and mechanisms of interindividual variability in response to food. The aim of this study was to evaluate peripheral blood mononuclear cells (PBMC) as a model system and readily available source of RNA to discern gene expression signatures in relation to personalized therapy of obesity. PBMC were collected from obese men before and after an 8-week low-calorie diet (LCD) to lose weight. Changes in gene expression before and after the LCD were initially screened using a DNA-microarray platform and validated by qRT-PCR. Global gene expression analysis identified 385 differentially expressed transcripts after the LCD. Further analyses showed a decrease in some specific oxidative stress and inflammation genes. Interestingly, expression of these genes was directly related to body weight, while a lower IL8 gene expression was associated with higher fat mass decrease. Collectively, these observations suggest that PBMCs are a suitable RNA source and model system to perform nutrigenomics studies related to obesity and development of personalized dietary treatments. IL8 gene expression warrant further research as a putative novel biomarker of changes in body fat percentage in response to an LCD

Time-dependent effects of a high-energy-yielding diet on the regulation of specific white adipose tissue genes

White adipose tissue development is regulated by many factors, including the energy content of food and the genetic background. Nevertheless, little is known about possible differential effects of high-fat palatable diets when fed for short or long-time periods. Thus, the expression of certain genes involved with lipid metabolism (peroxisome proliferator-activated receptor gamma, PPARγ2; retinoic receptors; fatty acid binding protein, aP2 and uncoupling proteins, UCP) may be affected by those dietary manipulations (high-energy-yielding diet and time duration of feeding). High-fat feeding for 8 days decreased mRNA UCP3 levels compared to control fed animals, while feeding for 30 days increased them over controls. Similar findings occurred for PPARγ2 and aP2. Furthermore, statistically significant associations were found among PPARγ2, aP2 and UCP3 mRNA levels. These data suggest a physiological time-dependent response seeking to prevent excessive fat deposition when animals are fed for short-term with a high amount of dietary fat, which was followed by an adaptive period to the high-energy content of diet throughout a coregulation among certain lipid metabolism related genes: PPARγ2, aP2, UCP3

Changes in UCP mRNA expression levels in brown adipose tissue and skeletal muscle after feeding a high-energy diet and relationships with leptin, glucose and PPARgamma

Brown adipose tissue and skeletal muscle are known to be important sites for nonshivering thermogenesis. In this context, it is accepted that uncoupling proteins (UCPs) are involved in such process, but little is known about the physiological regulation of these proteins as affected by the intake of a high-energy (cafeteria) diet inducing fat deposition. In this study, the UCP messenger RNA (mRNA) expression in interscapular brown adipose tissue (iBAT) and skeletal muscle was assessed to evaluate the influence of a dietary manipulation on energy homeostasis regulation. We report a statistically significant increase in mRNA levels of iBAT UCP1 and UCP3 and a statistical marginal rise in skeletal muscle UCP3 mRNA expression after feeding a high-energy diet, whereas no changes in UCP2 expression were found in either tissue. Furthermore, significant positive associations between iBAT UCP1 and UCP3 mRNA levels with serum leptin were found. Although the expression of the b3 adrenoceptor (b3AR) was about 50% in the lean controls compared with the obese group in iBAT, no statistically significant changes were observed concerning peroxisome proliferator-activated receptor g2 (PPARg2) mRNA levels in muscle or iBAT. We conclude that feeding a diet inducing weight and fat gain produces different outcomes on iBAT and skeletal muscle UCP mRNA expression, revealing a tissue-dependent response for the three UCPs. Results suggest that the regulation of UCP expression in both tissues under these specific dietary conditions may be related to leptin circulating levels

Up-regulation of a thermogenesis-related gene (UCP1) and down-regulation of PPARgamma and aP2 genes in adipose tissue: possible features of the antiobesity effects of a beta3-adrenergic agonist.

A number of experiments have demonstrated the antiobesity effects of beta(3)-adrenergic receptor stimulation by promoting thermogenesis and/or lipolysis. While many studies have been performed in order to develop beta(3)-adrenergic agonists as a novel strategy in the management of obesity, more information is needed about the mechanisms involved in thermogenesis and the actions of these drugs on adipocyte differentiation. To address this, the possible thermogenic and antiadipogenic properties of Tertatolol, a beta(3)-adrenergic agonist, in a diet-induced obesity model has been tested. Animals fed on a high-fat diet gained more weight and fat mass as compared with control and high-fat fed animals treated with Tertatolol. A RT-PCR was carried out in white adipose tissue specific genes involved in thermogenesis such as uncoupling proteins (UCPs) and adipogenesis such as peroxisome proliferator-activated receptor (PPARgamma2), retinoid receptors (RXRalpha/RARalpha), and fatty acid binding protein (aP2). Levels of UCP1 mRNA were augmented in the Tertatolol-treated group as compared to non-treated high-fat fed animals, while the beta(3)-adrenergic agonist treatment significantly decreased the expression levels of aP2 and transcription factors such as PPARgamma2 and the ratio RXRalpha/RARalpha as compared to obese rats. Altogether these data suggest that the antiobesity effects of beta(3)-adrenergic agonists are not limited to the promotion of thermogenesis and/or lipolysis and support the implication that these beta(3)-adrenergic agonists also affect fat deposition by impairing adipogenesis in white adipose tissue (WAT)

Profile of adipose tissue gene expression in premenopausal and postmenopausal women: Site-specific differences

OBJECTIVES: Menopause increases the risk of several pathologies, probably due to enlarged levels of visceral fat. Apart from morphological and endocrine changes, a cluster of genes, still not fully defined, may be involved in these alterations. The objectives of the present study, therefore, were to analyze differences in adipose tissue gene expression between premenopausal and postmenopausal women and to ascertain whether any differences were depot specific. METHODS: Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) biopsies were taken from 7 premenopausal and 7 postmenopausal women undergoing surgery because of morbid obesity. RNA was extracted, and the overall gene expression profile was analyzed by microarray analysis. RESULTS: In general, SAT genes were overexpressed, whereas VAT genes were down-regulated in premenopausal compared with postmenopausal women. We found 724 differentially expressed genes in SAT and 327 in VAT. These differences suggest that several biological processes, such as the immune system and other metabolic processes, were altered based on menopause status. Regarding individual genes, neurexin 3, metallothionein 1E, and keratyn 7 showed the most pronounced differences. Interestingly, the expression of these genes was related to body fat distribution. CONCLUSIONS: Our results reveal that menopause influences the adipose tissue expression of many genes, especially of neurexin 3, metallothionein 1E, and keratyn 7, which are associated with the alteration of several key biological processes, such as the immune system and cell metabolism. Gene expression in adipose tissue could be used for diagnosis and the development of new therapeutic strategies against obesity and related alterations, depending on menopause status.Peer reviewe

Differential expression of oxidative stress and inflammation related genes in peripheral blood mononuclear cells in response to a low-calorie diet: A nutrigenomics study

Nutrigenomics is a new application of omics technologies in nutritional science. Nutrigenomics aims to identify molecular markers of diet-related diseases and mechanisms of interindividual variability in response to food. The aim of this study was to evaluate peripheral blood mononuclear cells (PBMC) as a model system and readily available source of RNA to discern gene expression signatures in relation to personalized therapy of obesity. PBMC were collected from obese men before and after an 8-week low-calorie diet (LCD) to lose weight. Changes in gene expression before and after the LCD were initially screened using a DNA-microarray platform and validated by qRT-PCR. Global gene expression analysis identified 385 differentially expressed transcripts after the LCD. Further analyses showed a decrease in some specific oxidative stress and inflammation genes. Interestingly, expression of these genes was directly related to body weight, while a lower IL8 gene expression was associated with higher fat mass decrease. Collectively, these observations suggest that PBMCs are a suitable RNA source and model system to perform nutrigenomics studies related to obesity and development of personalized dietary treatments. IL8 gene expression warrant further research as a putative novel biomarker of changes in body fat percentage in response to an LCD.Peer reviewe