Centre for Advanced Research on Platelet Signaling and Thrombosis Biology (ICMR), Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India.
Centre for Advanced Research on Platelet Signaling and Thrombosis Biology (ICMR), Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India; Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India.
Thromb Res. 2020 Dec;196:175-185. doi: 10.1016/j.thromres.2020.08.033. Epub 2020 Aug 24.
AMP-activated protein kinase (AMPK) is a metabolic master switch that has critical role in wide range of pathologies including cardiovascular disorders. As AMPK-α2 knockout mice exhibit impaired thrombus stability, we asked whether pharmacological inhibition of AMPK with a specific small-molecule inhibitor, compound C, could protect against arterial thrombosis without affecting hemostasis. Mice pre-administered with compound C exhibited decreased mesenteric arteriolar thrombosis but normal tail bleeding time compared to vehicle-treated animals. Compound C potently restricted platelet aggregation, clot retraction and integrin activation induced by thrombin and collagen. It impaired platelet spreading on both immobilized fibrinogen and collagen matrices; it, however, had no significant effect on thrombin-induced phosphatidylserine exposure that is characteristic of procoagulant platelets. In parallel, compound C brought about significant drop in thrombin-induced phosphorylation of myosin light chain (MLC) and MLC phosphatase (MYPT1) as well as abrogated rise in level of RhoA-GTP in thrombin-stimulated platelets. Thus, effects of compound C on agonist-induced platelet responses could be at least in part attributed to modulation of cytoskeletal changes mediated by RhoA-MYPT1-MLC signaling. An ideal antithrombotic drug would spare hemostatic responses that maintain vascular integrity while preferentially protecting against thrombosis. The present study suggests that AMPK could be one such potential therapeutic target.
AMP 激活的蛋白激酶（AMPK）是一种代谢主开关，在包括心血管疾病在内的广泛病理中具有关键作用。由于 AMPK-α2 敲除小鼠表现出血栓稳定性受损，我们想知道是否可以通过特定的小分子抑制剂化合物 C 抑制 AMPK 来预防动脉血栓形成而不影响止血。与接受载体治疗的动物相比，预先给予化合物 C 的小鼠肠系膜小动脉血栓形成减少，但尾巴出血时间正常。化合物 C 强烈抑制凝血酶和胶原蛋白诱导的血小板聚集、血凝块回缩和整合素激活。它抑制血小板在固定化纤维蛋白原和胶原蛋白基质上的扩展；然而，它对凝血酶诱导的血小板促凝特性的磷脂酰丝氨酸暴露没有显著影响。平行地，化合物 C 导致凝血酶诱导的肌球蛋白轻链（MLC）和 MLC 磷酸酶（MYPT1）磷酸化以及在凝血酶刺激的血小板中 RhoA-GTP 水平升高显著下降。因此，化合物 C 对激动剂诱导的血小板反应的作用至少部分归因于 RhoA-MYPT1-MLC 信号介导的细胞骨架变化的调节。理想的抗血栓药物应保留维持血管完整性的止血反应，同时优先预防血栓形成。本研究表明，AMPK 可能是这样的潜在治疗靶点。
