Fig. 6.
Perturbation of cellular cholesterol affects hormone-stimulated proregion secretion and WPB exocytosis. (Ai–ii) Histamine-stimulated secretion of proregion from HUVECs pre-treated for 30 minutes with vehicle (control), 5 mM MβCD or 5 mM MβCD-Chol. Data were compared by Student's t-test (n = 3 separate experiments for i and ii). (B) Kinetics of histamine-evoked (100 µM) WPB exocytosis following the same treatment as detailed in A. Increases in fura-2 fluorescence ratios were not different between treatment groups; a trace averaged from seven individual cells is shown in Ai. (ii) Cumulative plots of WPB fusion times, normalised to the total number of fusion events for control (black trace, n = 2057 events), and cells treated with MβCD (dark grey trace, n = 1101 events) and MβCD-Chol (light grey trace, n = 2014 events). (iii) Summary of the mean delay between the [Ca2+]i rise and first fusion event (seconds), mean maximal rate of exocytosis (WPBs/second) and probability of WPB fusion (Pr, percent, note broken y-axis) for control (black bars, n = 43 cells), and cells treated with MβCD (dark grey bars, n = 35 cells) and MβCD-Chol (light grey bars, n = 42 cells). Data were compared by one-way ANOVA.