Fig. 8

Stat1-null cell line secretes macrophage migration stimulatory and inhibitory factors. Green fluorescent protein (GFP)-H2B-transduced RAW264.7 macrophage cells (RAW264.7/GFP-H2B) treated with CM of (a) EpH4, (b) SSM2, (c) Met1, or (d) NDL cells were analyzed using time-lapse imaging. a–d Images are GFP-H2B (green) in RAW264.7 cells and tracks of cells migrating. Color legend (bottom right corners of a–d) indicates the time course and reflects the position at a certain time point. Cell migration was evaluated on (e) track length and (f) migration speed at each time-lapse interval. g Graph shows the result of the Transwell migration assay with negative control (N_Ctrl; DMEM) and CM isolated from EpH4, SSM2, Met1, and NDL cells. h SSM2-CM showed inhibitory activity on macrophage migration activated by Met1-CM. The effect of conditioned medium of DMEM, Met1/DMEM (50%/50%), and Met1/SSM2 (50%/50%) on RAW264.7/GFP-H2B migration measured by time-lapse imaging is shown. i RAW264.7 migration activity in response to either control (Ctrl; DMEM), the extracellular vesicle (EV)-rich fraction, or the soluble fraction (Sol) of Met1- and SSM2-CM measured using the Transwell migration assay. The result indicates that the EV-rich fraction has a stimulatory activity on macrophage migration. Data are mean ± SE. ****p < 0.0001, ***p < 0.001, *p < 0.05. ns Not significant (t test)