Influence of PRCP depletion in cultured cells. (A) HUVECs were treated with control (CN) or PRCP siRNA overnight, and comparative PRCP expression levels were analyzed by immunoblot. Data are mean ± SEM of 3 samples. (B) DHE fluorescent images of siRNA-treated HUVECs were obtained after control (CN; n = 6) or PRCP knockdowns (n = 6). Data are a representative experiment on siRNA-treated cells, and the adjacent graph is the mean ± SEM of pixel density per nucleus measured by morphometric analysis of 6 experiments for each group. (C) DHE fluorescent image of MEFs from control (n = 10) and PRCPgt/gt (n = 11) embryos. The figure presented is a representative experiment on each of the cells, and the adjacent graph is the mean ± SEM of pixel density per nucleus measured by morphometric analysis of ≥ 10 experiments for each condition. (B-C) Photographed at 40× on a Nikon, TE200 immunofluorescent microscope aperture 0.75/0.17 WD 0.72 oil immersion. The relative DHE fluorescence was measured by morphometric analysis on 40× microscopic images using MetaMorph (Molecular Devices). (D) Protein C activation on HUVECs with control (CN) or PRCP siRNA treatment as measured by activated protein C hydrolysis of a chromogenic substrate. Data presented are the percentage activated protein C hydrolysis generated on HUVECs treated with PRCP siRNA versus control. Data are mean ± SEM of 6 experiments per condition. (E) Thrombomodulin (TM) in HUVECs treated with control (CN) or PRCP siRNA as seen on immunoblot. Data presented are the mean ± SEM ratio of TM antigen/GAPDH antigen of 4 experiments. (F) mRNA expression for eNOS from control (CN) or PRCP knockdown siRNA-treated HUVECs as measured by real-time PCR (control: n = 7, PRCP knockdown: n = 7). (G) An immunoblot for eNOS was performed on control and PRCP siRNA-treated HUVEC lysates. The normalized relative ratio of uncoupled:coupled eNOS in lysates from 3 samples of control or PRCP siRNA-treated cells were compared by analysis of band intensity using densitometer scanning. Immunoblot for GAPDH was used as a loading control. *P < .05.