TGFB1 and pulmonary fibrosis: It is noteworthy that, in contrast to these studies, we performed the loss-of-function experiment on COL20A1 to further verify its property of promoting ECM deposition in our model of TGF-β1-treated human bronchial epithelial cells, demonstrating the crucial role of COL20A1 in regulating the EMT and pulmonary fibrosis.