The Function And Its Mechanism Of Dual Antiplatelet Drugs To Target Bf0801 And P2y < Sub > 12 < / Sub > Receptor Affect Platelet Apoptosis Research

Though antiplatelet drugs are proven beneficial to patients with coronary heart disease and stroke, more effective and safer antiplatelet drugs are still needed. In this study we report the antiplatelet effects and mechanism of BF0801, a novel adenine derivative. BF0801dramatically inhibited platelet aggregation and ATP release induced by ADP,2MeSADP, AYPGKF, SFLLRN or convulxin without affecting shape change in vitro. It also potentiated the inhibitory effects of adenosine-based P2Y12antagonist AR-C69931MX or phosphodiesterase (PDE) inhibitor IBMX on platelet aggregation. The cAMP levels in both resting and forskolin-stimulated platelets were increased by BF0801suggesting its PDE inhibitor activity, which is further confirmed by the concentrationdependent suppression of BF0801on the native and recombinant PDE. Similar to AR-C69931MX, BF0801drastically inhibited2MeSADP induced adenylyl cyclase inhibition in platelets indicating its P2Y12antagonism activity, which is substantiated by the inhibition of BF0801on the interaction between ADP and P2Y12receptor expressed in CHO-K1cells measured by atomic force microscopy. Moreover, we confirmed the antiplatelet effects of BF0801using platelets from rats intravenously given BF0801. In summary, for the first time we developed a novel adenine derivative bearing dual activities of PDE inhibition and P2Y12antagonism, which may have therapeutic advantage as a potential antithrombotic drug. Platelets are small, anucleated fragments shed by megakaryocytes and circulate in the blood with an average lifespan of7-10days. Triggered by physiological and pathological stimuli, platelets are activated and experience adherence, shape change, aggregation, granule release, and TXA2synthesis, which play critical roles in haemostasis and thrombosis. Apoptosis is genetically programmed cell death morphologically characterised by nuclear condensation and cytoplasmic shrinkage. Recent studies demonstrate that despite being anuleate, depending on the stimulus levels, platelets also experience apoptosis, a series of responses different from activation including PS exposure on the platelet surface, depolarization of mitochondrial inner transmembrane potential, activation of caspase-3, Bax translocation and cytochrome C release. Platelet apoptosis plays an important role in platelet clearance from the circulation, thus determines the life span of platelets. Enhanced platelet apoptosis has also been implicated in a number of pathological processes, such as type2diabetes, immune thrombocytopenia, Bernard-Soulier syndrome and thrombocytopenic purpura induced by H. pylori or malaria. Considerable efforts have been made to explore the mechanism underlying platelet apoptosis. Among the platelet surface receptors intensively studied in platelet activation, PAR1, GPIb and GPIIbⅢa have been reported participating in platelet apoptosis. As the most successful target for antiplatelet drugs, P2Y12receptor plays a pivotal role in platelet activation and has been intensively studied in platelet activation; however, the role of P2Y12receptor in platelet apoptosis has not been reported. In this study we sought to explore the role of P2Y12receptor in platelet apoptosis and the underlying mechanism. Using platelets treated with ABT-737, ABT-263, and stored at37℃, combined with P2Y12receptor antagonists and P2Y12deficiency mice, we found that P2Y12activation protects human platelets against apoptosis via PI3k-dependent Bak/Bax inactivation.