Sensing of metabolic signals via GPR183 promotes occupation of lung macrophage niches by monocytes

Monocytes populate tissues when local niches are depleted of tissue-resident macrophages, yet the tissue-derived signals controlling monocyte-to-macrophage differentiation are largely undefined. Here, we discovered that the oxysterol receptor GPR183 positions monocytes to sense niche signals that induce lung macrophage differentiation. We found that interstitial macrophages that continuously turn over express the oxysterol receptor GPR183, whereas alveolar macrophages that derive from embryonic