Metabolomics identifies endocannabinoid system remodeling during obesity associated inflammation in adipose tissue

Visceral white adipose tissue (vAT) is more susceptible than subcutaneous white adipose tissue (scAT) to obesity-associated metaflammation, but the metabolic pathways accompanying this depot-specific transition remain incompletely defined. We profiled vAT and scAT from mice fed a control diet or a 60%-kcal high-fat diet (HFD) for 1 or 8 weeks. Untargeted metabolomics was integrated with targeted endocannabinoid quantification, gene-expression and promoter-associated chromatin analyses, adipocyte and stromal vascular fraction (SVF) measurements, cross-omics correlation analysis, and cell-culture perturbations. After 1 week, HFD induced relatively few metabolic changes, although vAT showed early alterations associated with sphingomyelin metabolism. By week 8, both depots exhibited extensive but distinct metabolic remodeling. The KEGG retrograde endocannabinoid-signaling pathway was the highest-ranked enriched pathway in vAT, with 2-arachidonoylglycerol (2-AG) among the most strongly altered metabolites. Targeted analysis confirmed selective 2-AG accumulation in vAT, accompanied by coordinated changes in genes and promoter-associated chromatin marks related to endocannabinoid synthesis, degradation and receptor expression. Cellular fractionation localized excess 2-AG predominantly to vAT adipocytes, whereas Cnr2 was enriched in the SVF and induced by HFD specifically in vAT. Cross-omics integration further revealed a denser and predominantly inverse transcript–metabolite association network in vAT than in scAT. Using macrophage–adipocyte co-culture and secretome profiling, we demonstrated that cannabinoid stimulation shifts activated macrophage outputs away from pro-inflammatory cytokines ( Il1b , Ccl2 ) toward extracellular matrix (ECM) proteoglycan remodeling and intercellular signaling.