CD84 Determines Differential Fates of Pro-fibrotic Macrophages [scRNA-seq]

We performed single-cell RNA sequencing (scRNA-seq) of whole-lung tissues from bleomycin-treated control mice and mice with monocyte-specific Cd84 deletion to investigate how CD84 regulates myeloid cell recruitment, differentiation, and function during pulmonary fibrosis. scRNA-seq identified distinct monocyte and macrophage populations.

CD84 was preferentially expressed in Spp1hi pro-fibrotic macrophages, and its expression progressively increased along the monocyte-to-pro-fibrotic macrophage differentiation trajectory. Cd84 deletion reduced the recruitment of monocyte-derived macrophages, inhibited their differentiation into Spp1hi macrophages, and shifted macrophage composition toward Il1rnhi macrophages associated with alveolar epithelial regeneration.