Fig. 3

Identification of sialylated integrin β1 on sEV. A Identification of integrin β1 on YTS-1 sEV by MS. B YTS-1 sEV were purified by density gradient centrifugation. Levels of two sEV markers (TSG101, CD63) and integrin β1 in fractions 1–12 were analyzed by western blotting, and sialic acid levels were analyzed by lectin blotting. C Integrin β1 on sEV was enriched by IP and sialylation of vesicular integrin β1 was analyzed by lectin blotting. D Integrin β1 knockdown in YTS-1 (termed shA/B/C). shC (termed Y-shβ1) was used for further assay. GAPDH was used as loading control. E Uptake of ExoTracker-labeled sEV from Y-vec, Y-shβ1, and Y/GPI-NEU1. F Y-vec sEV and Y-shβ1 sEV were treated with/ without sialidase and ExoTracker-labeled, and their uptake by HCV29 was analyzed by flow cytometry. G–I HCV29 was treated with Y-vec sEV or Y-shβ1 sEV, and proliferation (G), apoptosis (H), and migratory ability (I) were determined. J Effects of integrin β1 blockage on sEV uptake. K–M HCV29 was incubated with YTS-1 sEV pre-treated with IgG or integrinβ1 neutralizing antibodies, and proliferation (K), apoptosis (L), and migratory ability (M) were determined. N Levels of sialylated integrin β1 on sEV from plasma, determined by ELISA. O Levels of total integrin β1 in plasma determined by ELISA. P Levels of sialylated integrin β1 in plasma determined by ELISA