Acute Iron Deprivation Reprograms Human Macrophage Metabolism and Reduces Inflammation In Vivo

Summary Iron is an essential metal that fine-tunes the innate immune response by regulating macrophage function, but an integrative view of transcriptional and metabolic responses to iron perturbation in macrophages is lacking. Here, we induced acute iron chelation in primary human macrophages and measured their transcriptional and metabolic responses. Acute iron deprivation causes an anti-proliferative Warburg transcriptome, characterized by an ATF4-dependent signature. Iron-deprived human macrophages show an inhibition of oxidative phosphorylation and a concomitant increase in glycolysis, a large increase in glucose-derived citrate pools associated with lipid droplet accumulation, and modest levels of itaconate production. LPS polarization increases the itaconate:succinate ratio and decreases pro-inflammatory cytokine production. In rats, acute iron deprivation reduces the severity of macrophage-dependent crescentic glomerulonephritis by limiting glomerular cell proliferation and inducing lipid accumulation in the renal cortex. These results suggest that acute iron deprivation has in vivo protective effects mediated by an anti-inflammatory immunometabolic switch in macrophages.
Graphical Abstract
Highlights • Acute iron deprivation causes an atypical Warburg effect in human macrophages • Iron controls citrate and lipid pools and is essential for an intact TCA cycle • LPS polarization is limited in iron-deprived human macrophages • Acute iron deprivation reduces the severity of macrophage-driven glomerulonephritis
Iron is a crucial regulator of cell function, but its role in human macrophage immunometabolism is only partially understood. Pereira et al. show that acute iron deprivation in human macrophages causes anti-inflammatory immune and metabolic responses, and acute iron deprivation in rats reduces the severity of macrophage-driven renal inflammation.