Modulation of Platelet Activation and Thrombus Formation Using a Pan-PI3K Inhibitor S14161 |
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| Authors: | Wenxiu Yi Qiang Li Jian Shen Lijie Ren Xiaohui Liu Qi Wang Sudan He Qingyu Wu Hu Hu Xinliang Mao Li Zhu |
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| Institution: | 1. Cyrus Tang Hematology Center, Collaborative Innovation Center of Hematology, MOH Key Lab of Thrombosis and Hemostasis, Jiangsu Institute of Hematology, the First Affiliated Hospital, Soochow University, Suzhou, China.; 2. Department of Pathology and Pathophysiology, Zhejiang University, Hangzhou, China.; University of Kentucky, United States of America, |
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| Abstract: | The phosphatidylinositol 3–kinase (PI3K) signaling pathway is critical in modulating platelet functions. In the present study, we evaluated the effect of {"type":"entrez-protein","attrs":{"text":"S14161","term_id":"98844","term_text":"pir||S14161"}}S14161, a recently identified pan-class I PI3K inhibitor, on platelet activation and thrombus formation. Results showed that {"type":"entrez-protein","attrs":{"text":"S14161","term_id":"98844","term_text":"pir||S14161"}}S14161 inhibited human platelet aggregation induced by collagen, thrombin, U46619, and ADP in a dose-dependent manner. Flow cytometric studies showed that {"type":"entrez-protein","attrs":{"text":"S14161","term_id":"98844","term_text":"pir||S14161"}}S14161 inhibited convulxin- or thrombin-induced P-selectin expression and fibrinogen binding of single platelet. {"type":"entrez-protein","attrs":{"text":"S14161","term_id":"98844","term_text":"pir||S14161"}}S14161 also inhibited platelet spreading on fibrinogen and clot retraction, processes mediated by outside-in signaling. Using a microfluidic chamber we demonstrated that {"type":"entrez-protein","attrs":{"text":"S14161","term_id":"98844","term_text":"pir||S14161"}}S14161 decreased platelet adhesion on collagen-coated surface by about 80%. Western blot showed that {"type":"entrez-protein","attrs":{"text":"S14161","term_id":"98844","term_text":"pir||S14161"}}S14161 inhibited phosphorylation of Akt at both Ser473 and Thr308 sites, and GSK3β at Ser9 in response to collagen, thrombin, or U46619. Comparable studies showed that {"type":"entrez-protein","attrs":{"text":"S14161","term_id":"98844","term_text":"pir||S14161"}}S14161 has a higher potential bioavailability than {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002, a prototypical inhibitor of pan-class I PI3K. Finally, the effects of {"type":"entrez-protein","attrs":{"text":"S14161","term_id":"98844","term_text":"pir||S14161"}}S14161 on thrombus formation in vivo were measured using a ferric chloride-induced carotid artery injury model in mice. The intraperitoneal injection of {"type":"entrez-protein","attrs":{"text":"S14161","term_id":"98844","term_text":"pir||S14161"}}S14161 (2 mg/kg) to male C57BL/6 mice significantly extended the first occlusion time (5.05±0.99 min, n = 9) compared to the vehicle controls (3.72±0.95 min, n = 8) (P<0.05), but did not prolong the bleeding time (P>0.05). Taken together, our data showed that {"type":"entrez-protein","attrs":{"text":"S14161","term_id":"98844","term_text":"pir||S14161"}}S14161 inhibits platelet activation and thrombus formation without significant bleeding tendency and toxicity, and considering its potential higher bioavailability, it may be developed as a novel therapeutic agent for the prevention of thrombotic disorders. |
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