Diet-regulated production of PDGFcc by macrophages controls energy storage

Macrophages: key mediators of fat storage Recent work has suggested that macrophages may regulate adiposity, but the mechanisms underlying this process remain unresolved. Cox et al. report that a macrophage-derived growth factor, Pvf3, and its receptor on fat body cells are needed for lipid storage in fruit fly larvae (see the Perspective by O'Brien and Domingos). The mouse Pvf3 ortholog, PDGFcc, was similarly required to store fat in newborn and adult mice. When PDGFcc was blocked or deleted, food intake and absorption were normal, but mice increased their energy expenditure partly due to enhanced brown adipose tissue thermogenesis. PDGFcc was produced exclusively by fat-resident macrophages rather than by those mediating inflammation and insulin resistance. This work may inform future treatments for lipodystrophy, cachexia, and obesity. Science , abe9383, this issue p. eabe9383 ; see also abj5072, p. 24