Amyloid Beta Protein Precursor Influences Cerebral Thrombosis

描述（由申请人提供）：含有淀粉样蛋白β -蛋白前体（ABetaPP）的分泌型Kunitz蛋白酶抑制剂（KPI）结构域形式也被称为先前描述的细胞分泌型蛋白酶抑制剂指定的蛋白酶连接蛋白-2 （PN2）。我们实验室早期的大量工作表明，PN2/ABetaPP是几种关键的促血栓酶的有效抑制剂，可以在体外抑制血栓形成。这些定义PN2/ABetaPP的生化特征，加上其在大脑和循环血小板中的丰度，表明该蛋白在脑血管损伤发作期间调节血栓形成的作用。出血性和缺血性中风是主要的健康问题，可导致严重的衰弱和发病率。出血性和缺血性中风都涉及血栓形成前通路的改变。在这些有害血管事件中参与调节脑血栓形成的分子和机制的精确理解仍未得到解决。本研究的目的是确定ABetaPP的蛋白酶抑制特性在脑血管损伤期间调节脑血栓形成中的作用。因此，构成本研究基础的总体假设是，PN2/ABetaPP的蛋白酶抑制功能在脑血管损伤过程中对脑血栓形成起着重要的调节作用。这一建议的三个具体目的如下。首先，确定转基因小鼠中血小板PN2/ABetaPP的特异性过表达是否会减少血栓形成、脑损伤和与脑血管损伤相关的行为缺陷。其次，确定转基因小鼠脑内PN2/ABetaPP特异性过表达是否会调节脑出血和短暂局灶性缺血模型的脑血栓形成。第三，确定PN2/ABetaPP、淀粉样前体样蛋白2 （APLP2）或两者的蛋白酶抑制活性缺失是否会增加脑血管损伤模型中的血栓形成、脑病变和行为缺陷。总之，这些拟议的转化研究，源于我们之前对PN2/ABetaPP蛋白酶抑制特性的广泛体外研究，将为该蛋白目前尚不清楚的重要生理功能提供新的见解。这可能为制定调节脑血栓形成和限制出血性和缺血性中风对大脑的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.