Guiot et al. (2020) found that the macrophage-derived exosome miR-142-3p was able to reduce TGFβR1 expression and inhibit TGF-β-induced fibrotic responses in alveolar epithelial cells and lung fibroblasts by targeting TGFβR1. The finding of another study demonstrated that human umbilical cord mesenchymal stem cell-derived exosome let-7i-5p could target TGFβR1 and inhibit lung fibroblast activation via the TGFβR1/Smad3 signaling pathway in a silica-induced PF model (Xu et al., 2022). The gene discussed is SMAD3; the disease is pemphigus foliaceus.