Developmental endothelial locus-1 (Del-1) is a hemostatic factor in thrombotic stroke

 描述（由申请人提供）：AIS最常见由血栓性血管闭塞引发，随后发生一系列复杂事件，包括炎症反应，共同导致缺血性神经元功能障碍。尽管进行了深入的研究，但组织型纤溶酶原激活剂（tPA）是唯一获批的AIS治疗方法。然而，短暂的治疗窗口和治疗后出血并发症限制了其临床应用。因此，需要鉴定脑血栓形成和炎症调节中的新靶点，以将生理性止血和修复与病理性血栓形成分离。在这项提案中，我们专注于最近发现的抗炎蛋白，发育内皮基因座-1（Del-1），它在大脑中高度表达，我们假设也参与了导致AIS的血栓形成的发病机制。我们的数据表明Del- 1具有有效的抗血栓形成活性。我们认为Del-1结合了磷脂酰丝氨酸（PS）结合结构域介导的抗血栓活性和归因于整联蛋白阻断的抗炎作用。在缺血性血管损伤开始时，Del-1的下调或通过PS表达细胞对Del-1的摄取增加而引起的短暂消耗可能会加剧血栓形成并增加梗死面积。我们的初步数据首次表明，组成型Del-1缺陷是促血栓形成，增加梗死面积，并导致更广泛的坏死，在小鼠模型中风。用单剂量的融合蛋白进行干预，我们以nM浓度创建了具有人IgG Fc片段的重组（r）-Del-1，挽救了Del-/-小鼠的表型。我们的主要假设是Del-1是一种新的脑源性止血因子，在AIS的发病机制和潜在管理中发挥作用。这将在两个相互关联的目标中得到检验：目标1。我们将使用两种血管损伤模型、测量梗死面积的MRI成像技术和皮质血流量，更全面地描述Del-1缺乏对血栓形成和AIS发展的影响。目标二。我们将探索r-Del-1-Fc预防病理性血栓形成继发性扩张的潜力，同时使用125 I-纤维蛋白原和FITC-葡聚糖外渗最大限度地减少对止血的影响。在后续的研究中，我们将描绘的贡献PS和整合素结合域Del-1的作用，AIS的发展。该项目的成功完成将确定Del-1是一种新的脑血管内皮源性稳态抗血栓蛋白，与AIS的发病机制相关。虽然这些研究是初步的，但Del-1对病理性血栓形成和炎症的潜在影响使其成为一种有吸引力的新候选药物，有助于预防中风扩展和复发。

 DESCRIPTION (provided by applicant): AIS is most commonly initiated by thrombotic vascular occlusion, followed by a complex series events including an inflammatory response that together leads to ischemic neuronal dysfunction. Notwithstanding intensive research, tissue-type plasminogen activator (tPA) is the only approved treatment for AIS. However, the brief therapeutic window and post-treatment bleeding complications have limited its clinical use. Therefore, there is a need to identify novel targets in the regulation of cerebral thrombosis and inflammation to dissociate physiological hemostasis and repair from pathological thrombus formation. In this proposal we focus on a recently discovered anti-inflammatory protein, developmental endothelial locus-1 (Del-1), which highly expressed in the brain that we hypothesize is also involved in the pathogenesis of thrombosis that leads to AIS. Our data demonstrate that Del- 1 has potent anti-thrombotic activity. We propose that Del-1 combines anti-thrombotic activity mediated through it phosphatidylserine (PS) binding domain with anti-inflammatory actions that have been attributed to integrin blockade. Down-regulation of Del-1 or transient depletion by increased uptake of Del-1 by PS-expressing cells at the onset of ischemic vascular injury may exacerbate thrombus formation and increase infarct size. Our preliminary data show for the first time that constitutive Del-1 deficiency is prothrombotic, increase infarct size and causes more extensive necrosis in a murine model of stroke. Intervention with a single dose of a fusion protein we created recombinant (r)-Del-1 with human IgG Fc fragment at nM concentrations rescues the phenotype of Del-/- mice. Our main hypothesis is that Del-1 is a novel brain derived hemostatic factor that plays a role in the pathogenesis and potentially the management of AIS. This will be tested in two interrelated aims: Aim 1. We will more fully characterize the impact of Del-1 deficiency on the development of thrombosis and AIS using two models of vascular injury, MRI imaging techniques to measure infarct size, and cortical blood flow. Aim 2. We will explore the potential of r-Del-1-Fc to prevent secondary expansion of pathological thrombosis while minimizing effects on hemostasis using 125I-fibrinogen and FITC-dextran extravasation. In follow-on studies, we will delineate the contribution of the PS and integrin binding domains to Del-1's role in the development of AIS. Successful completion of this project will identify Del-1 as a novel cerebrovascular endothelium derived homeostatic anti-thrombotic protein relevant to the pathogenesis of AIS. Although these studies are preliminary, the potential impact of Del-1 on pathological thrombosis and inflammation makes it an attractive new candidate to help prevent stroke expansion and recurrence.