Biased PAR1 Agonism in Sickle Cell Disease

项目总结 标题：镰刀细胞病中偏向的PAR1激动剂 镰状细胞病是由β-珠蛋白基因的单核苷酸突变引起的，导致 导致慢性溶血性贫血和痛苦的血管闭塞危象(VOC)的红细胞生理改变 由微血管闭塞/停滞触发。挥发性有机化合物是镰状细胞住院的主要原因 病人。激活主要的凝血酶受体，即蛋白酶激活受体1(PAR1)，可以增强 内皮细胞与镰刀状红细胞之间的相互作用。在我最近发表的研究中，我证明了 非造血细胞上的PAR1缺乏或伏拉帕沙抑制PAR1的作用减弱 SCD小鼠模型中的微血管停滞。除凝血酶外，PAR1还可通过 活化蛋白C(APC)。APC介导的PAR1激活被称为“偏向激动症”。 因为它激活了与凝血酶不同的信号通路，最终诱导了细胞保护 和抗炎作用。我的中心假设是典型的凝血酶/PAR1信号 导致微血管停滞，而非规范的APC/PAR1信号减少微血管 瘀血和血栓性炎症。我假设诱导有益的偏向PAR1的信号将是 比完全抑制PAR1更有利，后者可以阻断有害的凝血酶- 依赖信令以及有益的APC信令。在第一个目标中，我将比较 凝血酶/PAR1和APC/PAR1信号在凝血、炎症和微血管阻塞中的作用 使用带有PAR1点突变的小鼠的镰状细胞小鼠，这些小鼠选择通过凝血酶或 APC。在第二个目标中，我将比较信号选择性形式的APC的治疗潜力， 3K3A-APC对PAR1的两种抑制剂Parmodin 2和Vorapaxar的抗炎、抗微血管作用 停滞，和急性胸腔综合征。最后，在第三个目标中，我将调查有偏见的PAR1的影响 镰刀鼠死亡率和终末器官损伤的激动剂。这些研究将调查 偏向的PAR1信号在SCD发病机制中的作用

PROJECT SUMMARY Title: Biased PAR1 Agonism in Sickle Cell Disease Sickle cell disease (SCD) is caused by a single nucleotide mutation in the β-globin gene, resulting in altered red cell physiology that drives chronic hemolytic anemia and painful vaso-occlusive crisis (VOC) triggered by microvascular occlusion/stasis. VOC is the leading cause of hospitalizations of sickle cell patients. Activation of the main thrombin receptor, protease activated receptor 1 (PAR1), enhances the interactions between endothelial cells and sickle RBCs. In my recently published study, I demonstrated that PAR1 deficiency on nonhematopoietic cells or inhibition of PAR1 with vorapaxar attenuates microvascular stasis in a mouse model of SCD. In addition to thrombin, PAR1 is also activated by activated protein C (APC). The APC-mediated activation of PAR1 is referred to as “biased agonism” because it activates a different signaling pathway than thrombin and ultimately induces cytoprotective and anti-inflammatory effects. My central hypothesis is that canonical thrombin/PAR1 signaling contributes to microvascular stasis whereas non-canonical APC/PAR1 signaling reduces microvascular stasis and thromboinflammation. I hypothesize that inducing beneficial PAR1 biased signaling will be advantageous compared to complete PAR1 inhibition, which blocks the deleterious thrombin- dependent signaling as well as beneficial APC signaling. In the first aim I will compare the roles of thrombin/PAR1 and APC/PAR1 signaling on coagulation, inflammation, and microvascular stasis in sickle cell mice using mice with PAR1 point mutations that select for activation by either thrombin or APC. In the second aim, I will compare the therapeutic potential of a signaling-selective form of APC, 3K3A-APC, to two inhibitors of PAR1, parmodulin 2 and vorapaxar, on inflammation, microvascular stasis, and acute chest syndrome. Finally, in the third aim, I will investigate the effects of biased PAR1 agonism on mortality and end-organ damage in sickle mice. These studies will investigate the role of biased PAR1 signaling in the pathology of SCD.