Fig. 4.
Platelet-derived TGFβ1 drives pulmonary fibrosis. (A) Histology of lung sections 4 wk after bleomycin-induced fibrosis. ΔPltTGFβ1 lungs were compared to TGFβ1fl/fl control lungs, Masson–Goldner’s trichrome staining (Scale bar, 50 µm), n = 6/group. (B) Quantification of lung collagen deposition from scanned whole slides from mice in frame A. (C) RT-PCR for collagen I gene expression in lung homogenates of ΔPltTGFβ1 mice and TGFβ1fl/fl control mice during bleomycin-induced fibrosis. (D) Collagen I–V protein content in lungs of ΔPltTGFβ1 mice and TGFβ1fl/fl mice, SIRCOL assay. (E) IL-27p28 in BALF of ΔPltTGFβ1 and TGFβ1fl/fl mice during bleomycin-induced lung fibrosis, ELISA. (F) Supernatants of activated washed platelets from ΔPltTGFβ1 mice or TGFβ1fl/fl control mice were transferred to cell cultures of C57BL/6 J bone marrow-derived macrophages (BMDM) before stimulation with LPS for 24 h and quantification of IL-27p28 release by ELISA. Frames B–E (4 wk of bleomycin i.t.) were done with numbers of mice as indicated by circles and frame F is representative of three independent experiments; Student’s t test or one-way ANOVA; *P < 0.05, **P < 0.01, ***P < 0.001.