GPR183-expressing monocytes interact with Ch25h ⁺ lung fibroblasts. (A) Experimental setup for immunofluorescence microscopy of Gpr183^GFP/+Ch25h^tdTom double reporter mice after intranasal LPS administration. Control mice received intranasal PBS. Lungs were harvested 3 days after LPS or PBS administration. (B) Representative microscopy images of lungs from LPS-treated Gpr183^GFP/+Ch25h^tdTom double reporter mice. Scale bars are 20 μm. Arrows indicate Gpr183-GFP⁺ CD68⁺MHCII⁻ monocytes and CD68⁺MHCII⁺ macrophages located near Ch25h-tdTomato⁺ cells. (C) Images showing co-staining of PDGFRα and tdTomato in lung fibroblasts. Scale bars are 10 μm. (D) Nearest distance between the indicated lung cell populations from Gpr183^GFP/+Ch25h^tdTom double reporter mice. Average distances and P values (by two-sided Mann–Whitney test) are shown at the top of each violin plot. Data in panels B–D are representative of two independent experiments with a total of n = 3 mice analyzed per group. Panel A was adapted from Servier Medical Art.