Hemostatic factors and sickle cell disease

摘要 这项研究计划的长期目标是确定中枢止血作用的机制 蛋白水解酶，凝血酶，有助于镰状细胞病(SCD)的病理发展。开创性的作用 凝血酶在止血和血管生物学中的作用被这种酶积极控制的事实所强调 纤维蛋白沉积、血小板激活和内皮细胞(EC)信号事件通过多种底物和 受体[例如，蛋白酶激活的受体、纤维蛋白原、因子XI和因子XIII]以及负性 通过激活蛋白C进一步控制凝血酶的产生，蛋白C是一种天然抗凝剂，已知 抗炎/细胞保护性能。凝血酶活性的控制已被广泛研究。 因为凝血酶介导的蛋白分解是生理止血和病理止血的基础 血管闭塞事件，包括心肌梗塞、静脉血栓形成和中风。然而，另一个 详细研究凝血酶和凝血酶靶标的动力是这些蛋白质还控制着血管 通透性/屏障功能、组织修复和炎症，这些共同促进了 多种炎症性疾病。鉴于循环中的镰状细胞会导致多种血管损伤， 闭塞事件和炎症变化，并考虑到局部和全身止血系统的激活 作为SCD的一个显著特征，凝血酶和凝血酶靶标是具有临床意义的主要候选对象。 镰状细胞病病理生物学的修饰物。该项目的目标集中在两个一般假设上：i) 凝血酶作为血管生物学、血小板/内皮细胞活化、纤维蛋白沉积和炎症的主要调节因子 过程是SCD病理的主要决定因素，并且ii)SCD相关的发病率可以得到改善 通过在凝血酶原/凝血酶和下游凝血酶水平上进行新的遗传或药物干预 底物。这些假设将通过研究来检验，这些研究的重点是定义 凝血酶原在Berkeley镰刀鼠多器官SCD病理发展和长期生存中的作用 (Hba0/Hbb0[TG(Human HBS)]+/+)(目标1)；了解凝血酶介导的、纤维蛋白(原)依赖的和 推动SCD病理的纤维蛋白(原)非依赖机制(目标2)；并确定潜在的益处 凝血酶靶向药物干预在限制小鼠SCD病理中的作用(目标3)。建议数 研究将首次清楚地了解止血因素在脑出血中的重要性。 SCD的发病机制，并可能阐明限制SCD诱导的发病率的新的治疗策略。

SUMMARY The long-term objective of this research program is to define the mechanisms by which the central hemostatic protease, thrombin, contributes to the development of sickle cell disease (SCD) pathologies. The seminal role of thrombin in hemostasis and vascular biology is underscored by the fact that this protease positively controls fibrin deposition, platelet activation, and endothelial cell (EC) signaling events via multiple substrates and receptors [e.g., protease-activated receptors, fibrinogen, factor XI, and factor XIII], as well as negatively controls further thrombin generation through the activation of protein C, a natural anticoagulant with known anti-inflammatory/cytoprotective properties. The control of thrombin activity has been intensely studied because thrombin-mediated proteolysis is fundamental to both physiological hemostasis and pathological vaso-occlusive events, including myocardial infarction, venous thrombosis and stroke. However, an additional driving force for detailed studies of thrombin and thrombin targets is that these proteins also control vascular permeability/barrier function, tissue repair, and inflammation, which together contribute to the development of multiple inflammatory diseases. Given that circulating sickle cells result in a combination of vascular damage, occlusive events and inflammatory changes, and given that local and systemic hemostatic system activation is a conspicuous feature of SCD, thrombin and thrombin targets are prime candidates to be clinically-significant modifiers of sickle cell disease pathobiology. The aims of this project center on two general hypotheses: i) thrombin, as a master regulator of vascular biology, platelet/EC activation, fibrin deposition and inflammatory processes, is a major determinant of SCD pathologies, and ii) SCD-associated morbidities can be ameliorated by novel genetic or pharmacological interventions at the level of pro/thrombin and downstream thrombin substrates. These hypotheses will be tested through studies that focus on defining the importance of prothrombin in the development of multi-organ SCD pathologies and long-term survival in Berkeley sickle mice (Hba0/Hbb0 [Tg(Human HbS)]+/+) (Aim 1); understanding the thrombin-mediated, fibrin(ogen)-dependent and fibrin(ogen)-independent mechanisms driving SCD pathologies (Aim 2); and establishing the potential benefit of thrombin-targeted pharmacological intervention in limiting SCD pathologies in mice (Aim 3). The proposed studies will provide for the first time a clear understanding of the significance of hemostatic factors in the pathogenesis of SCD and may illuminate novel therapeutic strategies for limiting SCD-induced morbidities.