Ectonucleotidases in Atherothrombosis and Stroke

描述（由申请方提供）：活化血小板释放的ADP招募附近的血小板，导致血栓病灶的爆炸性增生。从活化的血小板或受损细胞释放的ATP促进炎症。细胞外核苷酸的协调磷酸化水解，由胞外核苷酸酶CD 39（核苷酸二磷酸水解酶1）的顺序作用，将ATP？ADP？AMP）和CD 73（51核苷酸酶，将AMP？腺苷）是一种重要的内皮稳态机制，其限制血管界面处的血栓形成和炎症。在局灶性脑缺血的情况下，CD 39基因敲除小鼠表现出潜在的血栓前表型和比对照组更差的结果。这些小鼠可以通过保留腺苷三磷酸双磷酸酶活性的重组可溶性CD 39来拯救，而不会增加脑出血。此外，高胆固醇血症的ApoE/CD 39双敲除小鼠表现出过度的动脉粥样硬化形成，这与血小板和炎性细胞募集到发展中的斑块中的作用一致。这些数据表明，外核苷酸酶保护动脉粥样硬化血栓事件，并与中风的发病机制。实验将阐明CD 39和CD 73具有动脉粥样硬化保护作用的机制，重点是它们抑制血小板活化和炎症级联反应的能力，在对照或高胆固醇血症背景下使用野生型、cd 39或cd 73基因缺失小鼠。实验将使用solCD 39（和/或纯化的CD 73）作为单一疗法或作为低剂量溶栓疗法的辅助，测试外核苷酸酶是否改善动脉粥样硬化倾向性脑血管环境中的缺血性中风结果。这里的首要目标是描绘一个内源性级联反应，保护血管免受动脉粥样硬化血栓形成，并确定是否可以治疗利用，以改善缺血性卒中的结果。 与公共卫生的相关性：该项目将探索两种存在于血管内衬细胞上的蛋白质如何降解循环物质，否则这些物质会促进凝血，炎症和动脉粥样硬化。利用这些蛋白质的活性可能会导致一种新的方法来防止凝块形成和动脉粥样硬化，从而导致一个全新的，也许更安全的治疗中风。

DESCRIPTION (provided by applicant): ADP released from activated platelets recruits nearby platelets, resulting in explosive accretion of a thrombotic nidus. ATP, released from activated platelets or injured cells, promotes inflammation. The coordinated phosphohydrolysis of extracellular nucleotides, by the sequential actions of the ectonucleotidases CD39 (nucleotide diphosphohydrolase 1, converts ATP? ADP?AMP) and CD73 (51 nucleotidase, converts AMP?adenosine), is an important endothelial homeostatic mechanism which limits thrombosis and inflammation at the blood-vessel interface. CD39 gene null mice exhibit a latent prothrombotic phenotype and worse outcomes than controls in the setting of focal cerebral ischemia. These mice can be rescued by recombinant soluble CD39, which retains apyrase activity, without increasing intracerebral hemorrhage. Furthermore, hypercholesterolemic ApoE/CD39 double knockout mice exhibit exaggerated atherogenesis, consistent with a role for platelet and inflammatory cell recruitment into the developing plaque. These data suggest that ectonucleotidases protect against atherothrombotic events and are relevant to the pathogenesis of stroke. Experiments will elucidate mechanisms by which CD39 and CD73 are atheroprotective, focusing on their ability to suppress platelet activation and inflammatory cascades, using wild-type, cd39- or cd73-gene null mice in control or hypercholesterolemic backgrounds. Experiments will test whether ectonucleotidases improve ischemic stroke outcomes in an atherosclerosis-prone cerebrovascular milieu, using solCD39 (and/or purified CD73) as monotherapy or as an adjunct to low dose thrombolytic therapy. The overarching goal here is to delineate an endogenous cascade which protects vessels against atherothrombosis, and determine whether it may be therapeutically harnessed to ameliorate ischemic stroke outcomes. Relevance to Public Health: This project will explore how two proteins, which exist on cells lining blood vessels, degrade circulating substances which would otherwise promote clotting, inflammation, and atherosclerosis. Harnessing the activity of these proteins might lead to a new way of preventing clot formation and atherosclerosis, and thereby lead to a completely new and perhaps safer treatment for stroke.