Delayed targeting of CD39 to activated platelet GPIIb/IIIa via a single-chain antibody: breaking the link between antithrombotic potency and bleeding?
Delayed targeting of CD39 to activated platelet GPIIb/IIIa via a single-chain antibody: breaking the link between antithrombotic potency and bleeding?
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DOI：
10.1182/blood-2012-08-449694
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发表时间：
2013-04-18
期刊：
影响因子：
20.3
通讯作者：
Peter, Karlheinz
中科院分区：
文献类型：
--
作者：
Hohmann, Jan David;Wang, Xiaowei;Peter, Karlheinz
外三磷酸核苷二磷酸水解酶CD 39是一种很有前途的抗血栓治疗药物。它降解腺苷59-二磷酸（ADP），一种主要的血小板活化/募集剂。我们假设，在血栓形成过程中延迟富集CD 39将使全身浓度降低且安全，从而避免出血。我们使用单链抗体（scFv，对活化的GPIIb/IIIa具有特异性）来靶向CD 39。这应该允许延迟富集在生长的血栓上，而不是在血小板的初始密封层上，其还不表达活化的GPIIb/IIIa。将⑶ 39重组融合至活化的GPIIb/IIIa特异性scFv（tag-CD 39）和非功能性scFv（non-tag-CD 39）。Targ-CD 39在预防ADP诱导的血小板活化方面比non-tag-CD 39更有效。在小鼠颈动脉血栓形成模型中，non-targ-CD 39虽然对血管闭塞具有保护作用，但与尾部横断时的显著出血相关。相比之下，tag-CD 39集中在血栓部位;因此，与低10倍的CD 39剂量相似的剂量预防血管闭塞的程度与高剂量非tag-CD 39相似，而没有延长出血时间。在这种低浓度下，等摩尔剂量的非targ-CD 39在预防血管闭塞方面无效。因此，通过scFv将CD 39延迟靶向活化的血小板提供了强的抗血栓形成效力，并且还防止出血，从而促进CD 39走向临床应用。
The ecto-nucleoside triphosphate diphosphohydrolase CD39 represents a promising antithrombotic therapeutic. It degrades adenosine 59-diphosphate (ADP), a main platelet activating/recruiting agent. We hypothesized that delayed enrichment of CD39 on developing thrombi will allow for a low and safe systemic concentration and thus avoid bleeding. We use a single-chain antibody (scFv, specific for activated GPIIb/IIIa) for targeting CD39. This should allow delayed enrichment on growing thrombi but not on the initial sealing layer of platelets, which do not yet express activated GPIIb/IIIa. CD39 was recombinantly fused to an activated GPIIb/IIIa-specific scFv (targ-CD39) and a nonfunctional scFv (non-targ-CD39). Targ-CD39 was more effective at preventing ADP-induced platelet activation than non-targ-CD39. In a mouse carotid artery thrombosis model, non-targ-CD39, although protective against vessel occlusion, was associated with significant bleeding on tail transection. In contrast, targ-CD39 concentrated at the thrombus site; hence, a dose similar to 10 times less of CD39 prevented vessel occlusion to a similar extent as high-dose non-targ-CD39, without prolonged bleeding time. An equimolar dose of non-targ-CD39 at this low concentration was ineffective at preventing vessel occlusion. Thus, delayed targeting of CD39 via scFv to activated platelets provides strong antithrombotic potency and yet prevents bleeding and thereby promotes CD39 toward clinical use.