Inhibition of ASMase by functional inhibitors of ASMase attenuates LPS-induced TF procoagulant activity and ATP-induced TF decryption in human macrophages. Human MDMs were treated with saline (Con) or ASMase inhibitors desipramine (Des; 10 µM) or imipramine (Imi; 10 µM) for 1 hour. Thereafter, MDMs were left unstimulated (UN) or were stimulated with LPS (1 µg/mL) for 4 hours alone or LPS for 4 hours followed by Bz-ATP (200 µM) for 15 minutes. Following the treatments, MDMs were processed to measure cell surface TF activity (A), TF antigen levels by western blot analysis (B), or expression of ASMase and TF on the cell surface by immunofluorescence confocal microscopy (C). (B) TF band intensities on western blots were quantified by densitometry analysis (right panel). (C) ASMase and TF levels in the plasma membrane were quantified by measuring the fluorescence intensity of ASMase and TF staining, respectively (right panels). Original magnification ×63 for panel C. **P < .01, ***P < .001.