Project description:The association between central obesity and insulin resistance reflects the properties of visceral adipose tissue. Our aim was to gain further insight into this association by analysing the lipid composition of subcutaneous and omental adipose tissue in obese women with and without insulin resistance. Subcutaneous and omental adipose tissue and serum were obtained from 29 obese nondiabetic women, 13 of whom were hyperinsulinemic. Histology, and lipid and gene profiling were performed. In omental adipose tissue of obese, insulin-resistant women, adipocyte hypertrophy and macrophage infiltration were accompanied by an increase in GM3 ganglioside and its synthesis enzyme ST3GAL5; in addition, phosphatidylethanolamine (PE) lipids were increased and their degradation enzyme, PEMT, decreased. ST3GAL5 was expressed predominantly in adipose stromovascular cells and PEMT in adipocytes. Insulin resistance was also associated with an increase in PE lipids in serum. Total RNA was isolated and up to 400 ng of total RNA per sample was labelled and hybridized to Illumina HumanHT-12_V4 expression BeadChip platform. Paired subcutaneous and omental samples from 6 women were analysed.
Project description:The association between central obesity and insulin resistance reflects the properties of visceral adipose tissue. Our aim was to gain further insight into this association by analysing the lipid composition of subcutaneous and omental adipose tissue in obese women with and without insulin resistance. Subcutaneous and omental adipose tissue and serum were obtained from 29 obese nondiabetic women, 13 of whom were hyperinsulinemic. Histology, and lipid and gene profiling were performed. In omental adipose tissue of obese, insulin-resistant women, adipocyte hypertrophy and macrophage infiltration were accompanied by an increase in GM3 ganglioside and its synthesis enzyme ST3GAL5; in addition, phosphatidylethanolamine (PE) lipids were increased and their degradation enzyme, PEMT, decreased. ST3GAL5 was expressed predominantly in adipose stromovascular cells and PEMT in adipocytes. Insulin resistance was also associated with an increase in PE lipids in serum.
Project description:Macrophage-mediated inflammation is a major contributor to obesity-associated insulin resistance. The corepressor NCoR interacts with inflammatory pathway genes in macrophages, suggesting that its removal would result in increased activity of inflammatory responses. Surprisingly, we find that macrophage-specific deletion of NCoR instead results in an anti-inflammatory phenotype along with robust systemic insulin sensitization in obese mice. We present evidence that de-repression of LXRs contributes to this paradoxical anti-inflammatory phenotype by causing increased expression of genes that direct biosynthesis of palmitoleic acid and M-OM-^I3 fatty acids. Remarkably, the increased M-OM-^I3 fatty acid levels primarily inhibit NF-M-NM-:B-dependent inflammatory responses by uncoupling NF-M-NM-:B binding and enhancer/promoter histone acetylation from subsequent steps required for pro-inflammatory gene activation. This provides a mechanism for the in vivo anti-inflammatory insulin sensitive phenotype observed in mice with macrophage-specific deletion of NCoR. Therapeutic methods to harness this mechanism could lead to a new approach to insulin sensitizing therapies. ChIP-Seq and Gro-Seq profiling was performed in thioglycollate-elicited peritoneal macrophages treated as indicated.
Project description:Obesity is a risk factor for numerous metabolic disorders; however, not all obese individuals are prone to insulin resistance. The central aim of this study was to identify molecular pathways directly related to insulin resistance independent of BMI in obesity. We sought to determine the gene expression signature of adipose tissue in a body mass index (BMI)-matched obese cohort of patients that are either insulin sensitive or insulin resistant. We determined the global gene expression signatures of omental and subcutaneous adipose tissue samples obtained from insulin-sensitive obese and insulin-resistant obese patients undergoing gastric bypass surgery.
Project description:Obesity is a risk factor for numerous metabolic disorders; however, not all obese individuals are prone to insulin resistance. The central aim of this study was to identify molecular pathways directly related to insulin resistance independent of BMI in obesity. We sought to determine the gene expression signature of adipose tissue in a body mass index (BMI)-matched obese cohort of patients that are either insulin sensitive or insulin resistant. We determined the global gene expression signatures of omental and subcutaneous adipose tissue samples obtained from insulin-sensitive obese and insulin-resistant obese patients undergoing gastric bypass surgery. The SQ sample for Insulin Resistant Patient 6 has been removed from the study.
Project description:This experiment was designed to study if there are differences in gene expression in the adipose tissue of women affected by polycystic ovary syndrome (PCOS) compared to non-hyperandrogenic women. PCOS is the most common endocrinopathy in women of reproductive age, and is characterized by hyperandrogenism and chronic anovulation. This disease is frequently associated with obesity, insulin resistance, and defects in insulin secretion, predisposing these women to type 2 diabetes, atherosclerosis, and cardiovascular disease. We have applied high-density oligonucleotide arrays to omental adipose tissue samples obtained from eight morbidly obese PCOS patients and seven morbidly obese non-PCOS women at the time of bariatric surgery. Keywords: Disease state analysis
Project description:Obesity is a risk factor for numerous metabolic disorders; however, not all obese individuals are prone to insulin resistance. The central aim of this study was to identify molecular pathways directly related to insulin resistance independent of BMI in obesity. We sought to determine the gene expression signature of adipose tissue in a body mass index (BMI)-matched obese cohort of patients that are either insulin sensitive or insulin resistant.