Amyloid Beta Protein Precursor Influences Cerebral Thrombosis

描述(由申请人提供)：分泌型库尼茨蛋白抑制物(KPI)含有结构域的淀粉样β蛋白前体(ABetaPP)也称为先前描述的指定为蛋白酶Nexin-2(Pn2)的细胞分泌型蛋白抑制物。我们实验室的大量早期工作表明，PN2/ABetaPP是几种关键的血栓形成酶的有效抑制剂，并能在体外抑制血栓形成。这些明确的PN2/ABetaPP的生化特征，再加上它在脑和循环中的丰富，表明该蛋白在脑血管损伤期间调节血栓形成方面发挥了作用。出血性和缺血性中风是可能导致严重虚弱和发病的主要健康问题。出血性卒中和缺血性卒中都涉及血栓前通路的改变。在这些有害的血管事件中，涉及调节脑血栓形成的分子和机制的精确了解仍未解决。本研究的目的是明确ABetaPP的蛋白酶抑制特性在脑血管损伤时调节脑血栓形成中的作用。在这方面，构成这一建议基础的总体假设是，PN2/ABetaPP的蛋白酶抑制功能在调节脑血管损伤时的脑血栓形成方面发挥着重要作用。这项建议的三个具体目标如下。首先，确定在转基因小鼠中特异性地过表达血小板PN2/ABetaPP是否会减少与脑血管损伤相关的血栓形成、脑损伤和行为缺陷。其次，确定转基因小鼠脑内PN2/ABetaPP的特异性过表达是否会调节脑出血和短暂性局灶性脑缺血模型中脑血栓的形成。第三，在脑血管损伤模型中，确定PN2/ABetaPP、淀粉样前体蛋白2(APLP2)或两者的蛋白酶抑制活性缺失是否会增加血栓形成、脑损伤和行为缺陷。综上所述，这些拟议的翻译研究源于我们之前对PN2/ABetaPP的蛋白酶抑制特性的广泛体外工作，将为了解该蛋白目前尚不清楚的重要生理功能提供新的见解。这可能会为制定控制脑血栓形成和限制出血性和缺血性中风对大脑损害的策略提供新的途径。

DESCRIPTION (provided by applicant): Secreted Kunitz proteinase inhibitor (KPI) domain-containing forms of the amyloid beta-protein precursor (ABetaPP) are also known as the previously described cell secreted proteinase inhibitor designated protease nexin-2 (PN2). Extensive earlier work from our laboratory has shown that PN2/ABetaPP is a potent inhibitor of several key pro-thrombotic enzymes and can inhibit thrombosis in vitro. These defining biochemical features of PN2/ABetaPP, coupled with its abundance in brain and in circulating blood platelets, have suggested a role for this protein in regulating thrombosis during episodes of cerebral vascular injury. Hemorrhagic and ischemic strokes are major health issues that can lead to severe debilitation and morbidity. Both hemorrhagic and ischemic strokes involve alteration of pro-thrombotic pathways. A precise understanding of the molecules and mechanisms involved in regulating cerebral thrombosis during these deleterious vascular events remains unresolved. The goal of this study is to define the role of the proteinase inhibitory properties of the ABetaPP in regulating cerebral thrombosis during cerebral vascular injury. In this regard, the overall hypothesis that forms the basis for this proposal is that the proteinase inhibitory function of PN2/ABetaPP plays a significant role in regulating cerebral thrombosis during cerebral vascular injury. The three specific aims of this proposal are as follows. First, determine if specific over-expression of platelet PN2/ABetaPP in transgenic mice will decrease thrombus formation, brain lesion, and behavioral deficits associated with cerebral vascular injury. Second, determine if specific over- expression of PN2/ABetaPP in brain in transgenic mice will modulate cerebral thrombosis in models of intracerebral hemorrhage and transient focal ischemia. Third, determine if deletion of the proteinase inhibitory activity of PN2/ABetaPP, amyloid precursor-like protein 2 (APLP2), or both will increase thrombus formation, brain lesion, and behavioral deficits in models of cerebral vascular injury. Together, these proposed translational investigations, which stem from our extensive previous in vitro work on the proteinase inhibitory properties of PN2/ABetaPP, will provide new insight into important physiological functions of this protein that currently remain unknown. This may lead to new avenues for developing strategies to regulate cerebral thrombosis and limit damage to the brain as a consequence of hemorrhagic and ischemic stroke.