Inhibition of macropinocytosis prevents Alexa488-BSA uptake by rat pulmonary endothelial cells.
(A) RPMEC were serum starved for 4 h followed by pretreatment with various inhibitors of macropinocytosis for 30 min including amiloride (Na/H exchange inhibitor, 3 mM), Cytochalasin D (actin polymerization inhibitor, 10 µM), Gö6976 (PKC inhibitor, 10 µM), then cells were incubated with Alexa488-BSA (50 µg/ml) for 15 min and fixed with 2% paraformaldehyde for imaging. Images were taken by confocal microscopy (40× magnification). Representative images from three independent experiments are shown. (B) The fluorescence intensity was determined by Imaris software with data are present as mean ± SEM from three independent experiments. Significant differences from control (** P < 0.01, *** P < 0.001) were determined by one-way ANOVA followed by Tukey's multiple comparisons.