Fig. 4

Effect of TGF-β1 on PPP2R3A expression in HPF-a cells and the relationship between GREM1 and PPP2R3A. A Protein interaction map of the main components investigated in our research. B Three-dimensional structure of the PP2A protein. C Location of each subunit of PP2A. D, E In HPF-a cells, the expression of PPP2R3A first increased and then decreased over time. The expression levels at 1, 3, and 6 h were significantly different from those at 0 h (*p < 0.05). F Representative images of immunofluorescence staining show that TGF-β1 treatment increased the expression of PPP2R3A protein in HPF-a cells; scale bar = 20 μm. G The Ppp2r3a mRNA level increased over time, and the expression levels at 12 and 24 h were significantly different from those at 0 h (*p < 0.05). H, I Representative Western blot results showing that Grem1 knockdown partially reversed the upregulation of PPP2R3A induced by TGF-β1. *p < 0.05 indicates that the expression level of PPP2R3A in the si-Con group was higher than that in the control group after TGF-β1 treatment, showing successful establishment of the cell model. ^#p < 0.05 indicates that PPP2R3A was expressed at a lower level in the si-Grem1 group than in the si-Con group after TGF-β1 treatment