Fig. 7. Exosomal-TNFAIP8 prevents fibroblast from apoptosis through blocking p53 signal pathway.

a Diagram shows the experimental design. b NRK-49F cells incubated with exosomes (CTL-Exo or TGFβ-Exo, 30 μg/ml) were treated with or without MG132 for 6 h. Cell lysates were immunoprecipitated with anti-p53 antibody. The ubiquitination of the p53 was analyzed by western blotting using anti-ubiquitin antibody. c Co-immunoprecipitation assay show the status of p53 ubiquitination in NRK-49F cells after incubation with exosomes from different groups (30 μg/ml) as indicated and treated with MG132 for 6 h. d Western blotting analyses demonstrate protein expression of p53, cleaved caspase-3, FADD, Bax, c-myc, cyclin D1, fibronectin and α-SMA in different groups of NRK-49F cells. Numbers (1–3) indicate each individual treatment in a given group. Representative FACS analyses (e) and quantitative data (f) show the apoptotic cells after various treatments in NRK-49F cells. ^**P < 0.01, ^††P < 0.01 (n = 3). Graphic presentations show the relative level of cyclin D1 (g) and c-myc (h) mRNA measured by qPCR after various treatments in NRK-49F cells. ^**P < 0.01, ^††P < 0.01 (n = 6). i Representative micrographs show immunofluorescence staining of fibronectin in different groups as indicated. Arrows indicate positive staining. Scale bar, 50 µm. j Schematic presentation depicts the potential mechanism by exosomal-TNFAIP8 that prevents fibroblasts from apoptosis and promotes fibroblast activation through blocking p53 signal pathway. Data presented as mean ± S.E.M. of three or six independent experiments. p values were calculated using Student-Newman-Kuels test for multiple groups comparison.