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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

High-fat-fed C57Bl/6J FABP4/aP2 null mice develop obesity but not the related hyperglycemia or hyperinsulinemia characteristic of type II diabetes. FABP4/aP2 protein's function to bind fatty acids in the adipocytes may promote total body energy homeostasis by linking energy depots to the ability to express signaling molecules similar to leptin. To test this hypothesis, proteomic analysis of serum proteins from high-fat-fed wild-type and FABP4/aP2 null mice revealed that the GDF-3/Vgr-2 protein, a bone morphogenetic protein, was upregulated in C57Bl/6J FABP4/aP2 null mice. The increase in serum GDF-3/Vgr-2 protein was correlated with a 27-fold increase in adipose GDF-3/Vgr-2 mRNA. In contrast, leptin expression was unaltered between FABP4/aP2 null and wild-type animals. The expression of GDF-3/Vgr-2 mRNA was not substantially different in adipose tissue of db/db and tb/tb mice compared to wild-type controls. The expression of GDF-3/Vgr-2 mRNA was dependent upon the age and diet of the animals, declining as a function of age in high-fat-fed wild-type animals while increasing in the FABP4/aP2 null strain. These results identify GDF-3/Vgr-2 as an age- and fat-regulated, adipose-derived cytokine suggesting a linkage between adipocyte fatty acid metabolism and the expression of the bone morphogenetic family of differentiation regulators.
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PMID:Upregulation of bone morphogenetic protein GDF-3/Vgr-2 expression in adipose tissue of FABP4/aP2 null mice. 1139 90

Leptin is produced by adipose tissue and acts as a feedback signal to the hypothalamus controlling energy homeostasis, by reducing food consumption and increasing energy expenditure. Because serum leptin levels are highly correlated with body fat mass, they can be used as an index to predict obesity-related diseases. However, the identity of genetic factors that influence the obesity and the obesity-related metabolic disorders remains largely unknown. In this study, we performed a whole-genome scan search, using 382 F2 intercross progeny between the Otsuka Long-Evans Tokushima Fatty (OLETF) rat, an animal model for obese type 2 diabetes in human, and F344 rat, in order to identify loci responsible for the regulation of leptin and other obesity-related plasma substances. We have identified two quantitative trait loci (QTLs) contributing to serum leptin levels. These two loci, designated Olep1 [Chromosome (Chr) 2] and Olep2 (Chr 6), were homologous to those of human genome regions containing several potential candidate genes for obesity. These are fatty acid-binding protein 2 (FABP2), FABP4, and FABP5 for Olep1, and proopiomelanocortin (POMC) and glucose regulatory protein (GCKR) for Olep2.
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PMID:Serum leptin concentration is linked to chromosomes 2 and 6 in the OLETF rat, an animal model of type 2 diabetes with mild obesity. 1472 32

Obesity and type 2 diabetes are closely related, multifactorial metabolic conditions characterized by alterations in energy metabolism and glucose homeostasis, respectively. Peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-dependent transcription factor that regulates genes involved in lipid and glucose homeostasis, including the adipocyte-specific fatty acid-binding protein (FABP4). In turn, FABP4 binds fatty acids and transports them to the nucleus where the FABP4/fatty acid complex activates PPARgamma in a positive feedback loop. In this study, we tested the hypothesis that the polymorphisms, FABP4-376 and PPARgamma Pro12Ala, interactively influence insulin sensitivity and body composition in nondiabetic, Hispanic and non-Hispanic white males (n = 314) participating in the San Luis Valley Diabetes Study (SLVDS). Although the individual sites were not statistically significantly associated with any of the outcomes, we found statistically significant interaction terms in 2-way analysis of covariance (ANCOVA) models for homeostasis model assessment of insulin resistance (HOMA-IR) (P =.014) and lean mass (P =.019). While the PPARgamma Pro12Ala site was the only statistically significant predictor of fat mass in the 2-way model (P =.012), the FABP4 and PPARgamma main effect terms individually became stronger when considered in one model compared with the analysis of each polymorphism separately. These findings provide evidence that FABP4 and PPARgamma work together to influence a biologic pathway affecting insulin sensitivity and body composition, illustrating the importance of investigating the joint effect of genes in determining susceptibility for complex disease.
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PMID:Genetic variation in fatty acid-binding protein-4 and peroxisome proliferator-activated receptor gamma interactively influence insulin sensitivity and body composition in males. 1501 41

An increase in fat mass associated with obesity results from recruitment and differentiation of adipocyte progenitor cells. The precise origin of these cells is unknown, although accumulating evidence suggests that circulating stem cells can differentiate into cells of mesenchymal lineage. It is currently unclear whether a progenitor adipocyte population exists in circulation. One potential candidate is the fibrocyte, which may represent a common progenitor cell for several mesenchymal lineages. We demonstrate that these circulating progenitors become adipocytes when cultured under adipogenic conditions, with intracellular lipids accumulation and up-regulation of proteins specific for adipocyte differentiation, including leptin, PPARgamma, and FABP4. cDNA microarray analysis revealed gene clusters that were differentially regulated during adipogenesis of fibrocytes, which were similar to visceral and subcutaneous adipose tissue preadipocyte-to-adipocyte differentiation. Moreover, these progenitors engrafted and formed human adipose tissue following injection into SCID mice. Although fibrocytes express an array of chemokine receptors, we observed an up-regulation of CCR2 expression following fibrocytes differentiation into adipocytes, which was associated with increased chemotactic response to CCL2. This paradigm supports the notion that elevated CCL2 levels in visceral adipose tissue associated with Metabolic Syndrome is a chemotactic niche, whereby fibrocytes can home to and differentiate into adipocytes to perpetuate its tissue formation.
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PMID:Characterization of human fibrocytes as circulating adipocyte progenitors and the formation of human adipose tissue in SCID mice. 1618 61

Resistin is secreted from adipocytes, and high circulating levels have been associated with obesity and insulin resistance. To investigate whether resistin could exert autocrine effects in adipocytes, we expressed resistin gene in 3T3-L1 fibroblasts using a lentiviral vector, and selected several stably-transduced cell lines under blasticidin selection. We observed that 3T3-L1 adipocytes expressing resistin have a decreased gene expression for related transcriptional factors (CCAAT/enhancer binding protein alpha(C/EBPalpha), peroxisome proliferator-activated receptor gamma (PPARgamma), and adipocyte lipid binding protein (ALBP/aP2) which is one of target genes for the PPARgamma during adipocyte differentiation,. Overexpression of resistin increased the levels of three proinflammatory cytokines, tumor necrosis factor alpha (TNFalpha), interleukin 6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1), which play important roles for insulin resistance, glucose and lipid metabolisms during adipogenesis. Furthermore, overexpressing resistin in adipocytes inhibits glucose transport 4 (GLUT4) activity and its gene expression, reducing insulin's ability for glucose uptake by 30%. In conclusion, resistin overexpression in stably transduced 3T3-L1 cells resulted in: 1) Attenuation of programmed gene expression responsible for adipogenesis; 2) Increase in expression of proinflammatory cytokines; 3) Decrease in insulin responsiveness of the glucose transport system. These data suggest a new role for resistin as an autocrine/paracrine factor affecting inflammation and insulin sensitivity in adipose tissue.
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PMID:Proinflammatory cytokine production and insulin sensitivity regulated by overexpression of resistin in 3T3-L1 adipocytes. 1685 42

Obesity is associated with increased morbidity and mortality from cardiovascular disease, diabetes and cancer. Although obesity is a multi-factorial heterogeneous condition, fat accumulation in visceral depots is most highly associated with these risks. Pathological glucocorticoid excess (i.e. in Cushing's syndrome) is a recognised, reversible cause of visceral fat accumulation. The aim of this study was to identify depot-specific glucocorticoid-target genes in adipocyte precursor cells (preadipocytes) using Affymetrix microarray technique. Confluent preadipocytes from subcutaneous (SC) and omental (OM) adipose tissue collected from five female patients were treated for 24 h with 100 nM cortisol (F), RNA was pooled and hybridised to the Affymetrix U133 microarray set. We identified 72 upregulated and 30 downregulated genes by F in SC cells. In OM preadipocytes, 56 genes were increased and 19 were decreased. Among the most interesting were transcription factors, markers of adipocyte differentiation and glucose metabolism, cell adhesion and growth arrest protein factors involved in G-coupled and Wnt signalling. The Affymetrix data have been confirmed by quantitative real-time PCR for ten specific genes, including HSD11B1, GR, C/EBPalpha, C/EBPbeta, IL-6, FABP4, APOD, IRS2, AGTR1 and GHR. One of the most upregulated genes in OM but not in SC cells was HSD11B1. The GR was similarly expressed and not regulated by glucocorticoids in SC and OM human preadipocytes. C/EBPalpha was expressed in SC preadipocytes and upregulated by F, but was below the detection level in OM cells. C/EBPbeta was highly expressed both in SC and in OM preadipocytes, but was not regulated by F. Our results provide insight into the genes involved in the regulation of adipocyte differentiation by cortisol, highlighting the depot specifically in human adipose tissue.
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PMID:Expression profiling of 11beta-hydroxysteroid dehydrogenase type-1 and glucocorticoid-target genes in subcutaneous and omental human preadipocytes. 1703 48

The Wnt family of secreted signaling molecules has profound effects on diverse developmental processes, including the fate of mesenchymal progenitors. While activation of Wnt signaling blocks adipogenesis, inhibition of endogenous Wnt/beta-catenin signaling by Wnt10b promotes spontaneous preadipocyte differentiation. Transgenic mice with expression of Wnt10b from the FABP4 promoter (FABP4-Wnt10b) have less adipose tissue when maintained on a normal chow diet and are resistant to diet-induced obesity. Here we demonstrate that FABP4-Wnt10b mice largely avert weight gain and metabolic abnormalities associated with genetic obesity. FABP4-Wnt10b mice do not gain significant body weight on the ob/ob background, and at 8 weeks of age, they have an approximately 70% reduction in visceral and subcutaneous adipose tissues compared with ob/ob mice. Similarly, on the lethal yellow agouti (A(y)) background, FABP4-Wnt10b mice have 50-70% less adipose tissue weight and circulating leptin at 5 months of age. Wnt10b-Ay mice are more glucose tolerant and insulin sensitive than A(y) controls, perhaps due to reduced expression and circulation of resistin. Reduced expression of inflammatory cytokines may also contribute to improved glucose homeostasis.
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PMID:Wnt10b inhibits obesity in ob/ob and agouti mice. 1725 72

Glucocorticoids (GCs) have a profound effect on adipose biology increasing tissue mass causing central obesity. The pre-receptor regulation of GCs by 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) that activates cortisol from cortisone has been postulated as a fundamental mechanism underlying the metabolic syndrome mediating adipocyte hyperplasia and hypertrophy in the omental (OM) depot. Orbital adipose tissue (OF) is the site of intense inflammation and tissue remodelling in several orbital inflammatory disease states. In this study, we describe features of the GC metabolic pathways in normal human OF depot and compare it with subcutaneous (SC) and OM depots. Using an automated histological characterisation technique, OF adipocytes were found to be significantly smaller (parameters: area, maximum diameter and perimeter) than OM and SC adipocytes (P<0 x 001). Although immunohistochemical analyses demonstrated resident CD68+ cells in all three whole tissue adipose depots, OF CD68 mRNA and protein expression exceeded that of OM and SC (mRNA, P<0 x 05; protein, P<0 x 001). In addition, there was higher expression of glucocorticoid receptor (GR)alpha mRNA in the OF whole tissue depot (P<0 x 05). Conversely, 11beta-HSD1 mRNA together with the markers of late adipocyte differentiation (FABP4 and G3PDH) were significantly lower in OF. Primary cultures of OF preadipocytes demonstrated predominant 11beta-HSD1 oxo-reductase activity with minimal dehydrogenase activity. Orbital adipocytes are smaller, less differentiated, and express low levels of 11beta-HSD1 but abundant GRalpha compared with SC and OM. OF harbours a large CD68+ population. These characteristics define an orbital microenvironment that has the potential to respond to sight-threatening orbital inflammatory disease.
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PMID:Characterisation of 11beta-hydroxysteroid dehydrogenase 1 in human orbital adipose tissue: a comparison with subcutaneous and omental fat. 1728 28

To describe the function in terms of gene expression, and to find new factors, we performed random complementary DNA (cDNA) sequencing using a 3'-directed cDNA library that faithfully represents the composition of the messenger RNA (mRNA). Through a systematic search of active genes in adipose tissue, we found adiponectin, encoded by the most abundantly expressed gene in adipose tissue, termed apM1 (adipose most abundant gene transcript-1). Fat specific gene library generated in this Japanese Human Genome Project identified many other key molecules of this tissue such as leptin, PPARgamma and aP2 (adipocyte fatty acid binding protein, FABP4), in addition to apM1. Following 10 years, hundreds of clinical studies implicated the critical role of adiponectin in the metabolic syndrome. Also organized establishment of aP2 related mice model revealed the impact of this cytoplasmic fatty acid binding protein in the development of metabolic syndrome. In summary, investigating fat specific genes was amazingly powerful for analyses of the physiology of this tissue, as well as the etiology and complications of obesity.
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PMID:Role of adiponectin and adipocyte fatty acid binding protein in the metabolic syndrome. 1748 68

The aim of our work was to develop an assay for the determination of angiopoietin-like protein 3 (Angptl3) in human blood, and investigate its levels in healthy volunteers and donors suffer from metabolic syndrome and familiar hypercholesterolemia. We developed and evaluated the sandwich ELISA method for the quantitative determination of human Angptl3 in serum samples. We conducted also the pilot study on individuals with metabolic syndrome or familiar hypercholesterolemia and healthy probands. The following parameters were measured: blood pressure, waist circumference, Angptl3 serum levels, serum cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, insulin, glucose, A-FABP, and BMI and Quicki insulin sensitivity index was calculated. In the study on 93 healthy volunteers we demonstrated that sex or age is not the determinant for Angptl3 serum values. Futhermore, 118 individuals with metabolic syndrome and 200 patients with familiar hypercholesterolemia were tested and it was found that probands with metabolic syndrome or familiar hypercholesterolemia had higher Angptl3 values than healthy individuals from the first study (medians 289.5 vs. 277.1 vs. 224.8 ng/ml, p < 0.01). All of groups did not differ in sex or age. Angptl3 values correlated with the systolic blood pressure, LDL and A-FABP (p < 0.05). No connection of Angptl3 with triglycerides was found (presumably influences of statins, fibrates via PPARs, etc). However, we performed stepwise regression and found A-FABP and Angptl3 serum values as the independent markers for metabolic syndrome presence only (F ratio 29, p < 0.01). Then we adjusted Angptl3 to A-FABP (reputable metabolic syndrome marker) and recognised that Angptl3 is the A-FABP-independent marker. The pilot study supports the hypothesis about the role of Angptl3 as a new class of lipid metabolism modulator. Their values could be a new key predictors of metabolic syndrome. Further research is necessary to confirm our findings in individuals with dyslipidemia, obesity, CAD and different medication in order to assess Angptl3 value as a risk predictor of accelerated atherosclerosis.
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PMID:Angiopoietin-like protein 3: development, analytical characterization, and clinical testing of a new ELISA. 1806 51


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