Vesicles filled with lipids modulate macrophages | Science



Adipose tissue (adipose tissue) is a major energy storage site that responds to fluctuations in nutrient availability to maintain systemic metabolic homeostasis (1). Adipocytes absorb blood in circulating free fatty acids (FFA) and store them in lipid droplets in response to increased insulin concentrations (which occur after feeding); they then hydrolyze lipids to release FFAs under conditions of nutrient deprivation. A variety of other cell types are present in adipose tissue, including fibroblasts, endothelial cells, and adipose tissue macrophages (ATMs). In addition to their roles in immune surveillance and elimination of cell debris, ATMs play an important role in lipid buffer binding and in the regulation of adipose tissue function in healthy states and diseased states. (2). Due to the increasing incidence of chronic obesity in the world and related health problems, there is increasing interest in understanding the function of adipose tissue in physiological and pathological contexts. On page 989 of this issue, Flaherty et al. (3) report that adipocytes communicate with ATMs by releasing a distinct class of extracellular vesicles (EVs) called fat-derived adipocyte-derived exosomes (AdExos) that appear to come directly from adipocyte lipid droplets. The adoption of AdExos by Resident Vending Machines allows the direct transfer of lipids, revealing a form of intercellular communication and nutrient exchange with important implications for pathologies associated with obesity .

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