Together, our present work suggested that some paired receptors and ligands, such as CD74_APP, CD74_COPA, COL1A2_a2b1, COL3A1_a2b1, and FN1_a3b1, not only may mediate the cell communication between AT2 cells and fibroblasts, but also may facilitate the increase of lung fibrosis EMT-mediated by the inflammation (Fig. 4G). The gene discussed is APP; the disease is pulmonary fibrosis.