TGFB1 and idiopathic pulmonary fibrosis: Interestingly, COL7A1 mRNA expression has also been demonstrated to be triggered by TGF-β1 in primary ATII cells, as well as by a fibrosis cocktail (containing TGF-β1 and other IPF-relevant cytokines) in ATII cells derived from human induced pluripotent stem cells.45