An adipocyte-endothelial framework linking adipose tissue inflammation to cardiometabolic vulnerability in obesity.

Background: Obesity-related cardiometabolic disease is linked to impaired adipose tissue function, but the underlying molecular programs are difficult to assign to specific adipose-resident cell types, to mechanistically connect to the activation state of macrophages, and to distinguish from alterations that may normalize with weight loss. Methods: We integrated a layered design combining untargeted proteomics and lipidomics to define obesity-associated, cell-type-resolved molecular phenotypes across adipocytes and adipose microvascular endothelial cells, explore whether an inflammatory milieu reproduces adipose-resident cell dysfunction, and identify features that show evidence of recovery after weight loss. Next, we validated in adipose tissue transcriptomes the elements that exhibit the strongest association with dyslipidaemia, hypertriglyceridemia, and/or hyperglycaemia to identify gene signatures of cardiometabolic relevance. Results: Adipocytes from subjects with obesity show suppression of mitochondrial energy metabolism together with impaired lipid plasticity, as reflected by triglyceride remodelling. By mimicking an inflammatory milieu with macrophage-conditioned media, we reproduced many of these changes in adipocyte cultures. Endothelial cells exhibited yet another, opposite trajectory in obesity, with reduced cell-cycle signalling and increased mitochondrial activation, which were recapitulated in vitro when these cells were exposed, respectively, to the secretions of inflamed macrophages and adipocytes. Bulk adipose tissue proteomes and lipidomes showed evidence of metabolic improvement after weight loss, including restoration of mitochondrial and substrate-handling pathways alongside reciprocal triglyceride remodelling. Together with inflammation-responsive adipocyte mitochondrial and lipid-handling dysfunction, our cell-type-informed framework probes macrophage and adipocyte-to-endothelial activation in obesity, and delineates cross-context cellular programs associated with weight loss. Notably, when integrated with transcriptomic resources, these layers of information prioritized determinants linked to impaired metabolism, and were used to generate models that can assess cardiometabolic vulnerability in subjects with obesity (AUROC values between 0.88 and 0.99). Conclusions: Our study reveals adipocyte and endothelial cell-specific elements acting as molecular signatures of adipose tissue inflammation with cardiometabolic implications.