(A) Protein profile of human fibrotic pleura was performed by tandem mass tag–based proteomics. Ctrl, pleura from control group; TBPF, pleura from patients with tuberculous pleural fibrosis. (n = 4). (B) Volcano plot of differentially expressed genes. (C) Representative images of Masson’s trichrome staining in pleura from control group and patients with TBPF. Scale bars: 100 μm. (D) Representative images of IHC staining of versican in pleura of controls or patients. Scale bar: 100 μm. (E) Representative images of immunofluorescence staining of versican (red) and Wilms tumor 1 (green). Scale bars: 100 μm. (F) Representative images of immunofluorescence images of α-SMA (red) and Wilms tumor 1 (green). Scale bars: 100 μm. (G) Pleural effusion versican content by ELISA. (H) Correlation analysis between versican concentration in effusion and pleural thickness in patients with TBPF, r = 0.6614, P < 0.001. (I) Representative images of immunofluorescence staining of versican in PMCs incubated with TGF-β (5 ng/mL) or bleomycin (0.2 μg/mL) for 24 hours. (J–L) PMCs were incubated with TGF-β (5 ng/mL) for 24 hours, after which intracellular protein levels of versican, collagen I, and α-SMA were measured by Western blotting; mRNA levels of versican, collagen I, and α-SMA were detected by qRT-PCR at 12 hours. Data are presented as mean ± SEM. Statistical analyses were performed with unpaired Student’s t tests. n = 3, **P < 0.01, ***P < 0.001, ****P < 0.0001. (M–O) Primary rat PMCs were isolated and cultured with VCAN siRNA or control siRNA with TGF-β1 for 36 hours. Then, rat PMC ECM was prepared by decellularization. PMCs were treated by control ECM or versican-deficient ECM with or without recombinant versican (1 μg/mL) for 24 hours, after which fibronectin, collagen I, and α-SMA were detected by Western blotting (M and N) or qRT-PCR (O). Statistical analysis was performed by 1-way ANOVA. n = 3, **P < 0.01, ***P < 0.001, ****P < 0.0001.