A novel thrombolytic targeting Von Willebrand Factor (VWF) to treat ischemic stroke

项目总结 动脉血栓形成导致的急性缺血性卒中(AIS)是合并发病和 全球范围内的死亡率。重组组织型纤溶酶原激活剂(RtPA)是目前唯一被批准用于治疗AIS的药物。 不幸的是，只有大约5%-10%的AIS患者实际接受了rtPA。RtPA治疗的风险 包括症状性颅内出血(ICH)显著增加，高达6.4%的 接受药物治疗的患者。此外，rtPA仅在存在以下情况的患者中实现10%的再通 大血管闭塞(LVO)卒中。这些凝块通常富含血小板，众所周知，它们对 RTPA。迫切需要开发溶栓剂：1.靶向关键蛋白参与 卒中血栓结构，2.动脉闭塞再通，3.比rtPA更安全。 血管性血友病因子(VWF)是治疗AIS的最佳靶点。VWF与糖蛋白Ib(GPIB)结合 血小板受体复合体GPIb-IX-V以及与GPIIb-IIIa结合，导致血小板活化和聚集。 VWF也会自我结合，延伸到血管腔内，作为血小板和红细胞黏附的支架。 这些过程导致动脉血栓形成，就像在AIS患者中看到的那样。我们脑血栓的初步数据 来自中风患者的研究表明，大多数血栓都有一个富含VWF的血小板外壳，包裹着 血栓核心，为rtPA相关的动脉再通率低提供了一个解释。 适配子是以寡核苷酸为基础的药物，具有很高的亲和力和特异性抑制其靶蛋白。我们 分离并优化了与VWF结合并抑制VWF的RNA适配子(DTRI-031)。我们还有 设计了第二个寡核苷酸(DTRI-025)，可以在几分钟内完全逆转DTRI-031的活性。我们的 在血栓形成的小动物和大动物模型中的数据表明，DTRI-031既能预防血栓 形成和溶解完全形成动脉闭塞的效果优于rtPA。这项提案的总体目标是1) AIS患者血浆VWF升高与凝血VWF的相关性及2)DTRI-031对VWF的抑制作用 转化为对AIS患者的有效治疗。 我们将检验以下假设：1)VWF是治疗AIS的最佳靶点。我们的初步数据显示 LVO AIS患者血浆VWF显著升高。我们的初步数据已经复制了这些 在中风小鼠模型中的发现。2)DTRI-031能有效地溶解AIS血样中的凝块 患者和活体中的中风小鼠模型。此外，DTRI-025迅速逆转AIS中的DTRI-031活性 在体外和体内。3)DTRI-031治疗可改善AIS小鼠模型的预后 再通，缩小梗塞体积，促进功能恢复。我们的初步数据显示， 与对照组相比，接受DTRI-031治疗的小鼠卒中后脑梗塞体积缩小。最后，DTRI-031有一个 通过减少脑出血、脑水肿形成和血脑屏障破坏来改善安全性 AA与rtPA比较。

PROJECT SUMMARY Arterial thrombosis resulting in acute ischemic stroke (AIS) is the leading cause of combined morbidity and mortality worldwide. Recombinant tissue plasminogen activator (rtPA) is the only drug approved to treat AIS. Unfortunately, only ~5-10% of patients who present with AIS actually receive rtPA. Risks of rtPA treatment include a significant increase in symptomatic intracranial hemorrhage (ICH), which occurs in up to 6.4% of patients who receive the drug. Moreover, rtPA only achieves 10% recanalization in patients who present with large vessel occlusion (LVO) stroke. These clots, which are commonly platelet-rich, are notoriously resistant to rtPA. A critical need exists to develop thrombolytic agents that: 1. target critical proteins involved in stroke clot architecture, 2. recanalize arterial occlusions, and 3. have a safety profile superior to rtPA. Von Willebrand Factor (VWF) is an optimal target for AIS treatment. VWF binds to glycoprotein Ib (GPIb) of the platelet receptor complex GPIb-IX-V as well as to GPIIb-IIIa, resulting in platelet activation and aggregation. VWF also self-associates, extending into the vessel lumen as a scaffold for platelet and red blood cell adhesion. These processes result in arterial thrombosis as seen in AIS patients. Our preliminary data of cerebral thrombi from stroke patients show that the majority of clots have a platelet shell rich with VWF encapsulating the thrombus core, providing an explanation for the poor arterial recanalization rate associated with rtPA. Aptamers are oligonucleotide-based drugs that inhibit their target proteins with high affinity and specificity. We have isolated and optimized an RNA aptamer that binds to and inhibits VWF (DTRI-031). We have also designed a second oligonucleotide (DTRI-025) that fully reverses DTRI-031 activity within minutes. Our data in small and large animal models of thrombosis demonstrates that DTRI-031 both prevents thrombus formation and lyses fully formed arterial occlusions better than rtPA. The overall goals of this proposal are to 1) correlate elevated plasma VWF to clot VWF in AIS patients and 2) demonstrate VWF inhibition by DTRI-031 can translate into an effective treatment for patients who present with AIS. We will test the hypotheses that 1) VWF is an optimal target for AIS treatment. Our preliminary data shows that LVO AIS patients have significantly elevated plasma VWF. Our preliminary data has replicated these findings in a murine model of stroke. 2) DTRI-031 effectively lyses clots in vitro in blood samples from AIS patients and in vivo in a murine model of stroke. Moreover, DTRI-025 rapidly reverses DTRI-031 activity in AIS in vitro and in vivo. 3) DTRI-031 treatment improves outcomes in a murine model of AIS by increasing recanalization, decreasing infarct volume, and improving functional recovery. Our preliminary data reveals that DTRI-031-treated mice have reduced post-stroke infarct volumes compared to control. Finally, DTRI-031 has an improved safety profile by decreasing ICH, cerebral edema formation and blood-brain-barrier breakdown after AIS compared to rtPA.