PAPep inhibited U937 cells adhesion to TNF-α-activated HUVEC.

<p>(A) HUVEC were incubated with PAPep(1, 10, 50 µM) or PAPS(50 µM) for 18 h, then stimulated with TNF-α (10 ng/ml) for 6 h. CM-H₂DCFDA-labeled (green fluorescence) U937 cells were seed onto HUVEC and co-cultured for 30 min. After removing the non-adherent cells, adherent cells were fixed and stained with rhodamine phalloidin (red fluorescence), and were counted under a confocal laser scanning microscopy with magnification of 200×. Results are displayed individually or as merged images. Data represent one of three experiments with similar results. Scale bars, 10 µm. (B) Quantitative analysis of the binding of U937 cells to HUVEC presented by bar graphs. ##, P<0.01 compared with unstimulated cells, **, P<0.01 compared with TNF-α-stimulated cells. Data are expressed as mean±SD of results from three independent experiments, each performed in duplicate.