Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Amides of fatty acids with ethanolamine (FAE) are biologically active lipids that participate in a variety of biological functions, including the regulation of feeding. The polyunsaturated FAE anandamide (arachidonoylethanolamide) increases food intake by activating G protein-coupled cannabinoid receptors. On the other hand, the monounsaturated FAE oleoylethanolamide (OEA) reduces feeding and body weight gain by activating the nuclear receptor PPAR-alpha (peroxisome proliferator-activated receptor alpha). In the present report, we examined whether OEA can also influence energy utilization. OEA (1-20 microm) stimulated glycerol and fatty acid release from freshly dissociated rat adipocytes in a concentration-dependent and structurally selective manner. Under the same conditions, OEA had no effect on glucose uptake or oxidation. OEA enhanced fatty acid oxidation in skeletal muscle strips, dissociated hepatocytes, and primary cardiomyocyte cultures. Administration of OEA in vivo (5 mg kg(-1), intraperitoneally) produced lipolysis in both rats and wild-type mice, but not in mice in which PPAR-alpha had been deleted by homologous recombination (PPAR-alpha(-/-)). Likewise, OEA was unable to enhance lipolysis in adipocytes or stimulate fatty acid oxidation in skeletal muscle strips isolated from PPAR-alpha mice. The synthetic PPAR-alpha agonist Wy-14643 produced similar effects, which also were dependent on the presence of PPAR-alpha. Subchronic treatment with OEA reduced body weight gain and triacylglycerol content in liver and adipose tissue of diet-induced obese rats and wild-type mice, but not in obese PPAR-alpha(-/-) mice. The results suggest that OEA stimulates fat utilization through activation of PPAR-alpha and that this effect may contribute to its anti-obesity actions.
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PMID:Oleoylethanolamide stimulates lipolysis by activating the nuclear receptor peroxisome proliferator-activated receptor alpha (PPAR-alpha). 1512 13

Dietary conjugated linoleic acid (CLA) is being investigated for beneficial effects for disease prevention and treatment in a variety of experimental models, including obesity and type 2 diabetes. To date, rodent studies suggest that trans-10,cis-12 (t10,c12) CLA is associated with greater insulin resistance, despite lower body fat, and that a CLA mixture (and perhaps c9,t11) could be beneficial for the management of insulin resistance. Studies investigating the mechanisms by which CLA operates at the cellular level show that the primary targets for CLA are members of the nuclear receptor family, particularly the lipostat transcription factors peroxisome proliferator-activated receptor alpha (PPARalpha), PPARgamma, sterol regulatory element-binding protein 1c, and liver X receptor alpha. Consequently, the effects of CLA on glucose metabolism are likely secondary effects mediated through factors such as PPARgamma coactivator 1 that are controlled by these nuclear receptors. The different responses of normal compared with insulin-resistant obese rodents suggest that interactions of CLA isomers with the cellular components that contribute to development of metabolic syndrome require further investigation.
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PMID:Dietary conjugated linoleic acid and insulin sensitivity and resistance in rodent models. 1515 52

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor that plays a pivotal role in obesity and diabetes. PPARgamma has two isoforms, PPARgamma1 and PPARgamma2. We investigated the functional differences between PPARgamma1 and PPARgamma2 by selectively disrupting PPARgamma2 in mice. In contrast to the embryonic lethality of PPARgamma-deficient mice, PPARgamma2(-/-) mice survived. Although normal development was identified in other tissues we examined, PPARgamma2(-/-) mice exhibited an overall reduction in white adipose tissue, less lipid accumulation, and decreased expression of adipogenic genes in adipose tissue. In addition, insulin sensitivity was impaired in male PPARgamma2(-/-) mice, with dramatically decreased expression of insulin receptor substrate 1 and glucose transporter 4 in the skeletal muscle, but thiazolidinediones were able to normalize this insulin resistance. Consistent with in vivo data, PPARgamma2(-/-) mouse embryonic fibroblasts showed a dramatically reduced capacity for adipogenesis in vitro compared with wild-type mouse embryonic fibroblasts. Taken together, our data demonstrate that PPARgamma2 deficiency impairs the development of adipose tissue and insulin sensitivity. PPARgamma2(-/-) mice may provide a tool to study the role of PPARgamma2 in obesity and diabetes.
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PMID:Selective disruption of PPARgamma 2 impairs the development of adipose tissue and insulin sensitivity. 1524 58

Given the recent demonstration that oleoylethanolamide (OEA), a cannabinoid receptor-inactive N-acylethanolamine, decreases food intake by activating the nuclear receptor PPARalpha (peroxisome proliferator-activated receptor alpha) in the periphery, we here evaluated the effects of both saturated and unsaturated C18 N-acylethanolamides (C18:0; C18:1; C18:2) in mice feeding behavior after overnight starvation. Our results show stearoylethanolamide (SEA, C18:0) exerts, unlike other unsaturated C18 homologs, a marked dose-dependent anorexic effect evident already at 2 h after its intraperitoneal administration. In addition, oral administration of SEA (25 mg/kg) was also effective in reducing food consumption, an effect ascribed to the molecule itself and not to its catabolites. Moreover, although the anorexic response to oral administered SEA was not associated with changes in the levels of various hematochemical parameters (e.g., glucose, cholesterol, triglycerides, leptin) nor in liver mRNA expression of peroxisome proliferator-activated receptors (PPARs) including PPARalpha, the anorexic effect of SEA was interestingly accompanied by a reduction in liver stearoyl-CoA desaturase-1 (SCD-1) mRNA expression. As SCD-1 has been recently proposed as a molecular target for the treatment of obesity, the novel observation provided here that SEA reduces food intake in mice in a structurally selective manner, in turn, correlated with downregulation of liver SCD-1 mRNA expression, has the potential of providing new insights on a class of lipid mediators with suitable properties for the pharmacological treatment of over-eating dysfunctions.
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PMID:Stearoylethanolamide exerts anorexic effects in mice via down-regulation of liver stearoyl-coenzyme A desaturase-1 mRNA expression. 1528 50

Peroxisome proliferator-activated receptors (PPARs) were discovered over a decade ago, and were classified as orphan members of the nuclear receptor superfamily. To date, three PPAR subtypes have been discovered and characterized (PPAR $\alpha$, $\beta/\delta$, $\gamma$ ). Different PPAR subtypes have been shown to play crucial roles in important diseases and conditions such as obesity, diabetes, atherosclerosis, cancer, and fertility. Among the most studied roles of PPARs is their involvement in inflammatory processes. Numerous studies have revealed that agonists of PPAR $\alpha$ and PPAR $\gamma$ exert anti-inflammatory effects both in vitro and in vivo. Using the carrageenan-induced paw edema model of inflammation, a recent study in our laboratories showed that these agonists hinder the initiation phase, but not the late phase of the inflammatory process. Furthermore, in the same experimental model, we recently also observed that activation of PPAR $\delta$ exerted an anti-inflammatory effect. Despite the fact that exclusive dependence of these effects on PPARs has been questioned, the bulk of evidence suggests that all three PPAR subtypes, PPAR $\alpha, \delta, \gamma$, play a significant role in controlling inflammatory responses. Whether these subtypes act via a common mechanism or are independent of each other remains to be elucidated. However, due to the intensity of research efforts in this area, it is anticipated that these efforts will result in the development of PPAR ligands as therapeutic agents for the treatment of inflammatory diseases.
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PMID:Role of Peroxisome Proliferator-Activated Receptors in Inflammation Control. 1529 82

Impairment of peroxisome proliferator-activated receptor-gamma (PPAR-gamma), a nuclear receptor that regulates genes involved in lipid and glucose metabolism, may contribute to the onset of metabolic disorders such as diabetes and the accompanying dyslipidemia. Fat-derived tumor necrosis factor alpha (TNF-alpha) and the acute-phase response protein, C-reactive protein (CRP), may also have a role in the development of obesity-related insulin resistance and type 2 diabetes mellitus. In this study, a group of 14 naturally occurring, insulin-requiring, type 2 diabetic cynomolgus monkeys were used to evaluate the effects of the PPAR-gamma agonist, rosiglitazone, on glycemic and lipid parameters and serum levels of TNF-alpha and CRP. The animals were randomized into 2 groups of 7. One group was treated with 0.5 mg/kg rosiglitazone orally once a day for 7 weeks. Blood was collected for evaluation at baseline, at 2 and 7 weeks during the treatment period, and at 7 and 13 weeks after treatment. Daily insulin requirements were recorded during the entire study. Results showed daily exogenous insulin requirements were significantly reduced (P <.01) in those treated with rosiglitazone, while glycemic control was maintained. Plasma triglyceride concentrations were significantly lower (P <.01) whereas plasma cholesterol levels tended to be lower and high-density lipoprotein (HDL) concentrations tended to be higher after treatment. No significant differences were noted in TNF-alpha and CRP serum levels during the treatment period. Body weights remained steady in both groups during the study. These results suggest overall improvement in insulin regulation and lipid profiles during treatment with rosiglitazone.
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PMID:Rosiglitazone treatment improves insulin regulation and dyslipidemia in type 2 diabetic cynomolgus monkeys. 1533 71

Growth differentiation factor 3 (GDF-3) is structurally a bone morphogenetic protein/growth differentiation factor subfamily member of the TGF-beta superfamily. GDF-3 exhibits highest level of expression in white fat tissue in mice and is greatly induced by high fat diet if fat metabolic pathway is blocked. To identify its biological function, GDF-3 was overexpressed in mice by adenovirus mediated gene transfer. Mice transduced with GDF-3 displayed profound weight gain when fed with high fat diet. The phenotypes included greatly expanded adipose tissue mass, increased body adiposity, highly hypertrophic adipocytes, hepatic steatosis, and elevated plasma leptin. GDF-3 stimulated peroxisome proliferator activated receptor expression in adipocytes, a master nuclear receptor that controls adipogenesis. However, GDF-3 was not involved in blood glucose homeostasis or insulin resistance, a condition associated with obesity. In contrast, similar phenotypes were not observed in GDF-3 mice fed with normal chow, indicating that GDF-3 is only active under high lipid load. Thus, GDF-3 is a new non-diabetic adipogenic factor tightly coupled with fat metabolism.
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PMID:GDF-3 is an adipogenic cytokine under high fat dietary condition. 1535 31

During the last years various studies have been able to offer an insight into the regulation of appetite, satiety and energy balance, as well as adipocyte differentiation and the role of adipose tissue as an endocrine organ. These mechanisms add new aspects to the pathogenesis of obesity, but also to the development of weight-reducing medications. Life-style factors, including reduced physical exercise and a high calorie intake, are responsible for the increase in obesity in industrialized countries. As a result of twin and adoption studies, the genetic influence on the development of obesity is estimated to be 30-70%. As regards the common form of obesity, more than 70 gene loci have been described as possible candidate genes. These comprise genes involved in central nervous regulation systems, including leptin, the leptinreceptor, POMC, MCR-4, as well as energy expenditure and adipocyte differentiation such as beta-adrenergic receptors, UCPs, and the nuclear receptor PPARy. The common form of obesity seems to be mainly due to an interaction between genetic disposition and environmental factors.
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PMID:[Pathogenesis of obesity]. 1536 50

Variations of the small heterodimer partner (SHP, NR0B2) gene, an atypical nuclear receptor that inhibits transactivation by hepatocyte nuclear factor (HNF)-4alpha, are associated with obesity among Japanese. The purpose of the study was to evaluate the prevalence of SHP variants among obese Danish men. Using combined SSCP and heteroduplex analysis, we analyzed the entire coding region of SHP for variants in a cohort of 750 Danish men with early-onset obesity and genotyped a cohort of 795 nonobese control subjects using PCR-RFLP. Functional analyses of the identified coding region variants were performed in both MIN6-m9 and HepG2 cell lines. A total of five novel variants, including three missense variants (c.100C>G [p.R34G], c.278G>A [p.G93D], and c.415C>A [p.P139H]) and two silent variants (c.65C>T [p.Y22Y] and c.339G>A [p.P113P]) were identified. Moreover, the previously reported c.512G>C [p.G171A] polymorphism was identified. The 171A allele was not associated with obesity (p = 0.07). The 34G, 93D, and 139H-alleles were rare variants, which were found only among obese subjects. Among the four coding region variants, the 93D-allele showed a reduced in vitro inhibition of the HNF-4alpha transactivation of the HNF-1alpha promoter expression when expressed in MIN6-m9 and HepG2 cell lines (p<0.01). In contrast to reported findings among obese Japanese, functional variants are rare among Danish men. A functional 93D variant of SHP was identified in 1 out of 750 obese and in none of 795 nonobese control subjects. Further large-scale population studies are necessary to assess the clinical impact of this rare variant on obesity risk among European subjects.
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PMID:Mutation analysis of NR0B2 among 1545 Danish men identifies a novel c.278G>A (p.G93D) variant with reduced functional activity. 1545 58

Nuclear receptors are major targets for drug discovery and have key roles in development and homeostasis, as well as in many diseases such as obesity, diabetes and cancer. This review provides a general overview of the mechanism of action of nuclear receptors and explores the various factors that are instrumental in modulating their pharmacology. In most cases, the response of a given receptor to a particular ligand in a specific tissue will be dictated by the set of proteins with which the receptor is able to interact. One of the most promising aspects of nuclear receptor pharmacology is that it is now possible to develop ligands with a large spectrum of full, partial or inverse agonist or antagonist activities, but also compounds, called selective nuclear receptor modulators, that activate only a subset of the functions induced by the cognate ligand or that act in a cell-type-selective manner.
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PMID:Principles for modulation of the nuclear receptor superfamily. 1552 Aug 17


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