MADD promotes VWF secretion in endothelial cells. (A) HUVECs were transduced with shCTRL or shMADD and immunostained for VWF (green), vascular endothelial cadherin (VEcad) (red) and nuclei (blue). Boxed areas are magnified on the right (1) and below (2). Scale bars represent 10 µm. (B) The number of WPBs was quantified per cell (small dots) and averaged per image (large dots) in 15 shCTRL and 6 shMADD images. (C) Western blot analysis for VWF expression in shCTRL- and shMADD-transduced HUVECs. Data from enzyme-linked immunosorbent assay (ELISA) show (D) intracellular VWF content in unstimulated cells, (E) 30-minute histamine-stimulated VWF secretion in absolute amounts (expressed in pmol), and (F) as a percentage of intracellular content of resting or nonstimulated cells (data are from 5 biological replicates). (D-F) Data are shown as mean ± SEM and were analyzed by using an unpaired Student t test. *P < .05; **P < .01; ****P < .0001.