AIMS SCUBE1 [signal peptide-CUB-epidermal growth factor (EGF) domain-containing protein 1], expressed in endothelial cells (ECs) and platelets, exists in soluble or membrane forms. We previously showed that soluble SCUBE1 is a biomarker for platelet activation and also an active participant of thrombosis. However, whether the adhesive module of its EGF-like repeats is essential and the specific contribution of SCUBE1 synthesized in ECs or platelets to thrombosis in vivo remain unclear. METHODS AND RESULTS We generated new mutant (Δ2) mice lacking the entire EGF-like repeats to evaluate the module's functional importance during thrombogenesis in vivo. The Δ2 platelet-rich plasma showed markedly impaired platelet aggregation induced by agonists including adenosine diphosphate, collagen, the thrombin agonist PAR-4 peptide and the thromboxane A2 analogue U46619. Consistently, genetic ablation of the EGF-like repeats diminished arterial thrombosis and protected Δ2 mice against lethal thromboembolism. On flow chamber assay, whole blood isolated from Δ2 or wild-type (WT) mice pre-treated with blocking antibodies against the EGF-like repeats showed a significant decrease in platelet deposition and thrombus formation on collagen-coated surfaces under arterial shear rates. Moreover, we created animals expressing SCUBE1 only in ECs (S1-EC) or platelets (S1-PLT) by reciprocal bone-marrow transplantation between WT and Δ2 mice. The time of carotid arterial thrombosis induced by ferric chloride was normal in S1-PLT chimeric mice but much prolonged in S1-EC animals. CONCLUSIONS We demonstrate that platelet-derived SCUBE1 plays a critical role in arterial thrombosis via its adhesive EGF-like repeats in vivo and suggest targeting these adhesive motifs of SCUBE1 for potential anti-thrombotic strategy.

中文翻译：

---

源自血小板的SCUBE1的表皮生长因子样重复序列对于血栓形成至关重要。

AIMS SCUBE1 [含信号肽-CUB-表皮生长因子（EGF）结构域的蛋白质1]在内皮细胞（EC）和血小板中表达，以可溶性或膜形式存在。我们先前显示可溶性SCUBE1是血小板活化的生物标志物，也是血栓形成的积极参与者。但是，其EGF样重复序列的粘附模块是否必不可少，并且尚不清楚在EC或血小板中合成的SCUBE1对体内血栓形成的具体作用。方法和结果我们生成了新的突变型（Δ2）小鼠，该小鼠缺乏完整的EGF样重复序列，以评估该模块在体内血栓形成过程中的功能重要性。富含Δ2的血小板血浆显示激动剂（包括二磷酸腺苷，胶原蛋白，凝血酶激动剂PAR-4肽和血栓烷A2类似物U46619。一致地，EGF样重复的基因消融减少了动脉血栓形成，并保护Δ2小鼠免于致死性血栓栓塞。在流室分析中，从Δ2或野生型（WT）小鼠中分离的全血经抗EGF样重复序列的封闭抗体预处理后，在动脉剪切速率下，血小板沉积和胶原涂层表面的血栓形成显着减少。此外，我们通过在WT和Δ2小鼠之间进行骨髓移植，创建了仅在EC（S1-EC）或血小板（S1-PLT）中表达SCUBE1的动物。氯化铁诱导的颈动脉血栓形成时间在S1-PLT嵌合小鼠中是正常的，但在S1-EC动物中则大大延长了。