FIPI

FIPI inhibits both PLD1 and PLD2 in a dose-dependent manner, with 50% loss of activity observed at approximately 25 nM. FIPI efficiently crosses cell membranes and inhibits PLD1 and PLD2 action on their endogenous substrate in the cytoplasmic environment.^[1]

For the time-course study, cells are preincubated with 100 nM FIPI for 5, 10, 15, or 30 min followed by a 10-min incubation with 0.3% 1-butanol. For recovery experiments, cells are incubated with 2 μCi/ml[³H]palmitic acid and then switched to fresh growth medium containing 50 μg/ml cycloheximide. Thirty minutes later, one set of cells is treated with 100 nM FIPI for 30 min followed by three washes with PBS and addition of fresh growth medium containing cycloheximide. The cells are incubated for 1 or 8 h. During the last 30 min, FIPI is added to a second set of cells, after which all of the sets of cells are assayed for PLD activity.

Mice that receives FIPI at a dose of 3 mg/kg displayes reduced occlusive thrombus formation upon chemical injury of carotid arteries or mesenterial arterioles. Similarly, FIPI-treated mice has smaller infarct sizes and significantly better motor and neurological function 24 hours after transient middle cerebral artery occlusion. This protective effect is not associated with major intracerebral hemorrhage or prolonged tail bleeding times.^[2]