Lineage tracing reveals the origins and dynamics of macrophages in lung injury and repair

Macrophages play a vital role in tissue repair and regeneration following injury. However, the cell fate, dynamic responses, and functions of macrophages from various origins during lung injury and repair are not fully understood. Here, we used genetic lineage tracing and scRNA-seq approaches to explore the temporal and spatial roles of tissue-resident and infiltrating macrophages during pulmonary fibrosis. We observed a sharp reduction in tissue-resident macrophages during the early inflammatory phase, with their numbers stabilizing during recovery. Monocytes contributed substantially to the macrophage population during the fibrotic phase, initially differentiating into interstitial macrophages and later…