PAEP and idiopathic pulmonary fibrosis: Additionally, our CellChat analysis revealed an upregulation of pro-fibrosis signaling (such as COLLAGEN and ANGPTL) in the communication between IPF-fibroblasts and other fibroblasts, as well as an increase in GDF signaling in the communication between epithelial cells and IPF-fibroblasts (Figure 4H–J).