Paper Title
PREVENTIVE EFFECTS OF 2-METHOXYESTRADIOL, A NATURAL METABOLITE OF ESTRADIOL, ON PLATELET ACTIVATION AND THROMBUS FORMATION IN VITRO AND IN VIVO

Abstract
Running head: 2-Methoxyestradiolexerts antiplatelet and antithrombotic activities. 2-Methoxyestradiol (2-ME) is a biologically active metabolite of 17-estradiol. 2-ME has been reported to has little or no affinity for classical estrogen receptors, and prevent multiple proliferative disorders, including vascular occlusion, atherosclerosis, and pulmonary hypertension, via estrogen receptor-independent mechanisms, suggesting that 2ME may be a valuable therapeutic molecule for prevention and treatment of cardiovascular diseases; however, the effect of 2-ME on platelet activation and thrombus formation remains unclear.Thus, we further systemically investigated the antiplatelet and antithrombotic effect of 2-ME. Our preliminary results showed that 2-ME selectively inhibited collagen-induced platelet aggregation. 2-ME could block GPVI signaling, including Syk, PLC2, and PKC. Furthermore, 2-ME inhibited the activation of Akt and mitogen-activated protein kinases. Additionally, 2ME inhibited granule release and calcium mobilization. In thein vivo thrombus formation study, 2-ME protected against pulmonary thrombosis and delayed platelet plug formation in mesenteric vessels, but did not adversely affect normal hemostasis, suggesting that 2-ME shows relative safety in preventing thrombus formation. In conclusion, these preliminary results point towards 2ME possessing anti-platelet and anti-thrombotic activities via suppressing GPVI signaling. In addition, these findings support that 2-ME may provide therapeutic potentials in patients with cardiovascular diseases. Keywords: 2-Methoxyestradiol, Platelet activation, Thrombus formation