TGFB1 and idiopathic pulmonary fibrosis: In addition, matrix stiffening synergizes with TGF-β1 can promote mRNA expression of both col1a1 and mmp1 in IPF fibroblasts, and highly expressed MMP1 mainly presents in the vicinity of alveolar epithelial cells rather than in the interstitial space where collagen is deposited (Chuliá-Peris et al., 2022).