OBJECTIVEThis study was aimed to investigate the regulatory effect of protein disulfide isomerase (PDI) on platelet GPIbα ectodomain shedding.

METHODSThe washed platelets were obtained from healthy volunteers. Platelets were incubated with PDI inhibitor bacitracin before stimulation with PMA (Phorbol-12-myristate-13-acetate), dibucaine and collagen. The N-terminal domain of GPIbα in supernatant was detected by Western blot, the GPIbα expression and the intraplatelet ROS levels were measured by flow cytometry.

RESULTSneither GC content nor GPIbα expression was changed after the washed platelets from the healthy donors were incubated only with PDI inhibitor. The washed platelets were incubated with PDI inhibitor before stimulation with different stimulin, PMA, dibucaine or collagen, and then GPIbα was cleaved and ROS levels were elevated more than that in the controls.

CONCLUSIONPDI participates in the induced GPIbα ectodomein shedding, and the effect of PDI in this process maybe depend on the change of ROS level inside platelets. These results might provide a new point of view for the platelet drug development.