Project description:Bisphenol A (BPA) is a xenobiotic endocrine disrupting chemical. In vitro and in vivo studies indicated that BPA alters endocrine-metabolic pathways in adipose tissue increasing the risk of developing metabolic disorders. BPA effects on human adipocytes, specifically in children, are poorly investigated. To investigate in childhood the effect of exposure to BPA on metabolic disorders we analyzed in vitro the effects of environmentally relevant doses of BPA on gene expression of mature human adipocytes from pre-pubertal lean patients and on related physiological outcomes. Adipocytes from children were treated in vitro with BPA and gene expression was evaluated by qRT-PCR. Genome wide analyses were performed using GeneChip Human Gene 1.0 ST array. Lipid content in adipocytes was estimated by ORO staining and Triglyceride Quantification Kit. Secreted IL-1beta, in adipocytes culture medium, and insulin, in PANC-1 culture medium, were performed using ELISA assays. BPA was found to promote up-regulation of ER? and ERR?, and down-regulation of GPR30 expression modulating estrogen signaling and following a non-linear dose-response. Microarray data analysis demonstrated that BPA increases the gene expression of pro-inflammatory cytokines and lipid metabolism-related FABP4 and CD36 in adipocytes. PCSK1 resulted the most interesting gene being down-regulated by BPA thus impairing insulin production in pancreas. BPA promotes inflammation and lipid metabolism dysregulation in adipocytes from lean children. Moreover, PCSK1 can be a key gene in BPA action modulating insulin production. Exposure to BPA in childhood may be an important risk factor in developing obesity and metabolic disorders. Three prototypic situations were analyzed (5 replication each): untreated cells (C), 10 nM BPA treated cells (BPA), 1 nM 17-beta Estradiol treated cells (ES).
Project description:Bisphenol A (BPA) is a xenobiotic endocrine disrupting chemical. In vitro and in vivo studies indicated that BPA alters endocrine-metabolic pathways in adipose tissue increasing the risk of developing metabolic disorders. BPA effects on human adipocytes, specifically in children, are poorly investigated. To investigate in childhood the effect of exposure to BPA on metabolic disorders we analyzed in vitro the effects of environmentally relevant doses of BPA on gene expression of mature human adipocytes from pre-pubertal lean patients and on related physiological outcomes. Adipocytes from children were treated in vitro with BPA and gene expression was evaluated by qRT-PCR. Genome wide analyses were performed using GeneChip® Human Gene 1.0 ST array. Lipid content in adipocytes was estimated by ORO staining and Triglyceride Quantification Kit. Secreted IL-1β, in adipocytes culture medium, and insulin, in PANC-1 culture medium, were performed using ELISA assays. BPA was found to promote up-regulation of ERα and ERRγ, and down-regulation of GPR30 expression modulating estrogen signaling and following a non-linear dose-response. Microarray data analysis demonstrated that BPA increases the gene expression of pro-inflammatory cytokines and lipid metabolism-related FABP4 and CD36 in adipocytes. PCSK1 resulted the most interesting gene being down-regulated by BPA thus impairing insulin production in pancreas. BPA promotes inflammation and lipid metabolism dysregulation in adipocytes from lean children. Moreover, PCSK1 can be a key gene in BPA action modulating insulin production. Exposure to BPA in childhood may be an important risk factor in developing obesity and metabolic disorders.
Project description:Adipocytes isolated from lean and obese postmenopausal women with no significant differences in metabolic syndrome parameters demonstrate changes in multiple inflammatory, metabolic and structural gene families. Purified adipocyte samples were isolated from subcutaneous adipose tissue surgical biopsies of 7 obese (BMI>30) and 7 lean (BMI<25) postmenoposal women and gene expression was quantified with Agilent-014850, 4X44K human whole genome platform arrays (GPL6480)
Project description:Adipocytes isolated from lean and obese postmenopausal women with no significant differences in metabolic syndrome parameters demonstrate changes in multiple inflammatory, metabolic and structural gene families.
Project description:White adipose tissue (WAT) is a key regulator of systemic energy metabolism, and impaired WAT plasticity characterized by enlargement of preexisting adipocytes associates with WAT dysfunction, obesity and metabolic complications. However, the mechanisms that retain proper adipose tissue plasticity required for metabolic fitness are unclear. Here, we comprehensively showed that adipocyte-specific DNA methylation, manifested in enhancers and CTCF sites, directs distal enhancer-mediated transcriptomic features required to conserve metabolic functions of white adipocytes. Particularly, genetic ablation of adipocyte Dnmt1, the major methylation writer, led to increased adiposity characterized by increased adipocyte hypertrophy along with reduced expansion of adipocyte precursors (APs). These effects of Dnmt1 deficiency provoked systemic hyperlipidemia and impaired energy metabolism both in lean and obese mice. Mechanistically, Dnmt1 deficiency abrogated mitochondrial bioenergetics by inhibiting mitochondrial fission and promoted aberrant lipid metabolism in adipocytes, rendering adipocyte hypertrophy and WAT dysfunction. Dnmt1-dependent DNA methylation prevented aberrant CTCF binding and, in turn, sustained the proper chromosome architecture to permit interactions between enhancer and dynamin-related protein gene Drp1 in adipocytes. Also, adipose DNMT1 expression inversely correlated with adiposity and markers of metabolic health, but positively correlated with AP-specific markers in obese human subjects. Thus, these findings support strategies utilizing Dnmt1 action on mitochondrial bioenergetics in adipocytes to combat obesity and related metabolic pathology.
Project description:This study examines the transgenerational adipocyte (fat cell) epigenetic alterations in F3 generation obese and lean rats ancestrally exposed to DDT and atrazine. Adipocytes were isolated from the gonadal fat pad of F3 generation 1-year old rats ancestrally exposed to DDT, atrazine, or vehicle control in order to obtain adipocyte DNA for DNA methylation analysis. Observations indicate that there were differential DNA methylated regions (DMRs) in the adipocytes with the lean or obese phenotypes compared to control normal (non-obese or lean) populations. Interestingly, there were epigenetic changes that were distinct when comparing the lean and obese DMRs between the control and exposure lineage groups. DMR gene associations were identified which included common set of genes previously shown to associate with adipocyte pathology. The comparison of epigenetic alterations indicated that there were substantial overlaps between the different treatment lineage groups for both the lean and obese phenotypes. Novel correlated genes and gene pathways associated with DNA methylation were identified, and may aid in the discovery of potential therapeutic targets for metabolic diseases such as obesity.
Project description:To better understand the molecular basis of the reproductive health effects of bisphenol A (BPA) on humans, a genome-wide screening was applied to identify novel targets of low-dose bisphenol A exposure in huamn skin fibroblast cells (hSFCs) derived from hypospadias patient children. Three hSFCs were collected at National Research Institute for Child Health and Development, Japan. Gene expression profiles of hSFCs were measured at 24 hours after exposure to 10nM BPA, 0.01nM 17β-estradiol (E2) and 1nM 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Differentially expressed genes following chemical treatments were identified by unpaired Student’s t test with P values cut off by 0.05 and fold change of more than 1.2 and selected for the network generation and pathway analysis using Ingenuity Pathways Analysis (IPA) program. As the result, 71 genes (42 downregulated and 29 upregulated), 814 genes (371 downregulated and 443 upregulated), and 824 genes (344 downregulated and 480 upregulated) were identified significantly differently expressed in response to BPA, E2, and TCDD, respectively. The network analysis indicated that the most associated network fuctions of genes genes with altered expression profile derived from microarray analysis were “Endocrine System Disorders, Gastrointestinal Disease, Genetic Disorder”, “Cellular Growth and Proliferation, Skeletal and Muscular System Development and Function, Cell Cycle”, and “Post-Translational Modification, Genetic Disorder, Hematological Disease” in response to BPA, E2, and TCDD, respectively. Gene expression profiles of 3 hSFCs derived from hypospadias patient children were measured at 24 hours after exposure to 10nM BPA, 0.01nM E2 and 1nM TCDD.
Project description:Development of insulin resistance is a key pathogenic component underlying metabolic syndrome and Type 2 diabetes (T2DM). Despite its importance, the molecular mechanisms underlying insulin resistance are poorly understood. Genome-wide association studies for T2DM and other metabolic traits have led to the identification of many candidate SNPs, but the majority of these SNPs are noncoding and determination of associated causal genes and/or specific tissue sites of action have been difficult. Adipocytes are critical regulators of mammalian metabolic homeostasis, with important effects on appetite, satiety, glucose and lipid homeostasis, energy expenditure, blood pressure, and immune function. Although insulin resistance (IR) in skeletal muscle, the major source of glucose disposal, is responsible for the bulk of the hyperglycemia observed in T2DM, muscle IR KO mice are generally healthy, IR also occurs in adipocytes, and inflammation within adipose tissue has been proposed as a primary mediator of IR, resulting in excess release of free fatty acids as well as alterations in adipokine release. Absence of adipose tissue, as observed in various lipodystrophies, or adipocyte-specific knockout of genes such as GLUT4 or insulin receptor, also alter systemic IR and T2DM risk. Transcriptional changes in adipocytes associated with metabolic disease. Despite the importance of adipocytes to metabolic disease, we have a poor understanding of how the adipocyte transcriptome changes in the disease state. Studies investigating transcriptional changes in whole adipose tissue have shown decreases in genes involved in adipogenesis, as well as alterations in inflammation, mitochondrial metabolism, lipid metabolism, detoxification, and insulin signaling. However, the vast majority of these studies use total adipose tissue samples, which does not allow for the exclusive evaluation of gene expression in mature adipocytes due to the substantial number of nonadipocyte cells (immune cells, fibroblasts, endothelial cells, pre-adipocytes, and mesenchymal cells) that also reside in adipose tissue. This is particularly relevant when studying metabolic disorders related to obesity-associated insulin resistance because these conditions are characterized by an increased influx of inflammatory cells into the adipose tissue.
Project description:The aim of the project was to compare global gene expression in adipocytes from obese patients and lean controls. Subcutaneous adipose tissue was collected from severely obese patients undergoing bariatric surgery (average body-mass index (BMI) of 45.5 kg/m2 (n = 12, thereof 4 men) and healthy lean patients undergoing hernia repairs (average BMI of 24.2 kg/m2 (n = 12, thereof 7 men), between 27 and 56 years of age. Adipocytes were isolated by collagenase treatment of adipose tissue, followed by filtering and centrifugation. Floating adipocytes were lysed in Qiazol before RNA purification and microarray analysis.