PPS can significantly inhibit the ECM components in human lung fibrosis (HLFs) cells treated with TGF-β1, and inhibit Smad2/3 phosphorylation even reduce TβRI and TβRII, but it has no effect on TβRIV and can also inhibit medium MMP-2/MMP-9 expression (Jiang et al., 2020). The gene discussed is MMP9; the disease is pulmonary fibrosis.