Fig. 7: FRMD6 mediates TGF-β-induced senescence but not myofibroblast differentiation.

a–e FRMD6 was knocked down and its effect was evaluated in TGF-β-stimulated cells. a Quantification of SA-β-Gal staining. b Immunoblotting analysis. c Immunofluorescence. Triple staining for FRMD6, p21 and α-SMA was conducted in control and FRMD6 knockdown cells after stimulation with TGF-β (10 ng/ml). Quantification of p21 (d) and α-SMA (e) positive cells in control or FRMD6 siRNA-treated cells. Error bars indicate means ± SEM from three independent experiments. ****p < 0.0001, t-test. f Schematic model for a specific role of FRMD6 in TGF-β-induced senescence but not myofibroblast differentiation. g Representative immunohistochemical images. Serially sectioned lung tissues from IPF patients were subjected to immunohistochemistry with the indicated antibodies. The rectangular areas in red (left column) are enlarged in the right column. Scale bars, 50 μm (left column); 100 μm (right column). h Representative Immunofluorescence images. Human IPF lung tissues were co-stained with FRMD6, p16, and α-SMA. FF, fibroblastic foci. Dotted lines denote the border between FF and lining cells that face the cystic space. Scale bars, 50 μm. i Quantification of FRMD6 and p16 co-staining FF in lining cells (shown in h). The size of FF denotes the long diagonal length in μm. N = 9 IPF patients.