Fig. 3.
TGFβ1 is released by platelets in response to externalized histones. (A) Platelets were isolated from C57BL/6 J mice and activated with purified histones (50 µg/mL) or thrombin (100 ng/mL) for 10 min before quantification of TGFβ1 in supernatants. (B) TGFβ1 release from platelets after incubation with recombinant human histones (H2A, H2B, H2, H4), citrullinated histone H3, human thrombin, and untreated (Ctrl), 10 min. (C) Isolated platelets from mice with platelet-specific gene deletion of TGFβ1 (ΔPltTGFβ1) mice and littermate controls (TGFβ1fl/fl) were activated with thrombin (100 ng/mL) for 10 min before quantification of TGFβ1 in supernatants. (D) Plasma concentrations of TGFβ1 in mice with platelet-specific deletion compared to littermate controls, 4 wk after bleomycin. (E) ΔPltTGFβ1 mice and TGFβ1fl/fl control mice received purified histones i.t. (100 µg/mouse) or PBS i.t. (sham) and TGFβ1 was detected in BALF after 8 h. (F) TGFβ1 in BALF of mice with platelet-specific deletion compared to TGFβ1fl/fl littermate controls and C57BL/6 J (WT) mice, 24 h after bleomycin. TGFβ1 was measured by ELISA in all frames. Frames A–C are representative of three independent experiments and frames D–F were done with numbers of mice as indicated by circles; Student’s t test or one-way ANOVA; **P < 0.01, ***P < 0.001, ****P < 0.0001, ns: not significant.