fig1

Figure 1. Transformation pathways of fibroblast subpopulations during pulmonary fibrosis. In homeostasis, SCUBE2⁺ alveolar fibroblasts support alveolar type II (AT2) cells. Under fibrotic stimulation, mediated by TGF-β signaling, these fibroblasts shift into an SAA3⁺ inflammatory state that recruits neutrophils and monocytes, and subsequently differentiate into CTHRC1⁺ fibrotic fibroblasts, which deposit collagen within the alveolar lumen.