No abstract

ObjectiveHuman white adipose tissue (AT) is a metabolically active organ with distinct depot-specific functions. Despite their locations close to the gastrointestinal tract, mesenteric AT and epiploic AT (epiAT) have only scarcely been investigated. Here, we aim to characterise these ATs in-depth and estimate their contribution to alterations in whole-body metabolism.DesignMesenteric, epiploic, omental and abdominal subcutaneous ATs were collected from 70 patients with obesity undergoing Roux-en-Y gastric bypass surgery. The metabolically well-characterised cohort included nine subjects with insulin sensitive (IS) obesity, whose AT samples were analysed in a multiomics approach, including methylome, transcriptome and proteome along with samples from subjects with insulin resistance (IR) matched for age, sex and body mass index (n=9). Findings implying differences between AT depots in these subgroups were validated in the entire cohort (n=70) by quantitative real-time PCR.ResultsWhile mesenteric AT exhibited signatures similar to those found in the omental depot, epiAT was distinct from all other studied fat depots. Multiomics allowed clear discrimination between the IS and IR states in all tissues. The highest discriminatory power between IS and IR was seen in epiAT, where profound differences in the regulation of developmental, metabolic and inflammatory pathways were observed. Gene expression levels of key molecules involved in AT function, metabolic homeostasis and inflammation revealed significant depot-specific differences with epiAT showing the highest expression levels.ConclusionMulti-omics epiAT signatures reflect systemic IR and obesity subphenotypes distinct from other fat depots. Our data suggest a previously unrecognised role of human epiploic fat in the context of obesity, impaired insulin sensitivity and related diseases.

Most information on molecular processes accompanying and driving adipocyte differentiation are derived from rodent models. Here, a comprehensive analysis of combined transcriptomic and proteomic alterations during adipocyte differentiation in Simpson–Golabi–Behmel Syndrome (SGBS) cells is provided. The SGBS cells are a well‐established and the most widely applied cell model to study human adipocyte differentiation and cell biology. However, the molecular alterations during human adipocyte differentiation in SGBS cells have not yet been described in a combined analysis of proteome and transcriptome. Here a global proteomic and transcriptomic data set comprising relative quantification of a total of 14372 mRNA transcripts and 2641 intracellular and secreted proteins is presented. 1153 proteins and 313 genes are determined as differentially expressed between preadipocytes and the fully differentiated cells including adiponectin, lipoprotein lipase, fatty acid binding protein 4, fatty acid synthase, stearoyl‐CoA desaturase, and apolipoprotein E and many other proteins from the fatty acid synthesis, amino acid synthesis as well as glucose and lipid metabolic pathways. Preadipocyte markers, such as latexin, GATA6, and CXCL6, are found to be significantly downregulated at the protein and transcript level. This multi‐omics data set provides a deep molecular profile of adipogenesis and will support future studies to understand adipocyte function.