Reduction of Annexin A5 in Antiphospholipid Pregnancy Loss

描述(申请人提供)：反复妊娠丢失是抗磷脂综合征(APS)的标志，APS是一种复杂的主要高凝障碍，目前通过现象学替代试验诊断。APS与一系列血栓并发症有关，包括反复妊娠丢失、中风、深静脉血栓形成和肺栓塞。胎盘抗凝蛋白Annexin A5(AnxAS)是一种有效的磷脂结合蛋白，能在含有阴离子磷脂的膜上形成二维抗凝晶体屏障。AnxAS在胎盘合体滋养层细胞顶膜上高度表达，处于促进绒毛间隙血液流动性的解剖位置。这一应用的核心假设是致病抗磷脂(APL)抗体与APL抗体的主要辅因子(32-糖蛋白I)上的特定结构域结合。这些结果导致在合体滋养层细胞的顶端表面形成大分子抗体-抗原复合体，从而在AnxAS抗凝剂屏障中产生缺陷，从而促进 凝血反应和降低胎盘循环中的血液流动性。我们已经为这一假说提供了强有力的证据，并已开始开发针对这种疾病机制的创新治疗方法，并进行机制测试，以确定对AnxAS抗凝剂活性的抵抗。这笔赠款将扩大上述调查结果的范围，具体目标如下： 1)研究APL抗体对AnxAS抗凝血屏障的影响 胎盘滋养层细胞的顶膜。 2)将第一个特定目标的发现转化为针对这种疾病的创新治疗 机制和机制分析，以诊断疾病。这些目标将通过原子力显微镜、椭圆偏振法、结合研究、凝血酶研究(使用PL双层、培养的胎盘细胞和胎盘绒毛)和翻译测试来实现。 该项目将对阐明妊娠丢失的新机制做出重大贡献。 在一种严重的疾病中，缺乏既定的病理生理学，并将打开新的 基于机械的诊断和治疗的方法。

DESCRIPTION (provided by applicant): Recurrent pregnancy losses are a hallmark of the antiphospholipid syndrome (APS), a complicated major hypercoagulable disorder without an established mechanism that is currently diagnosed with phenomenologic surrogate tests. APS is associated with a host of thrombotic complications including recurrent pregnancy losses, stroke, deep vein thrombosis and pulmonary embolism. The placental anticoagulant protein, annexin A5 (AnxAS) is a potent phospholipid (PL)-binding protein that forms 2-dimensional anticoagulant crystal shields over membranes containing anionic PLs. AnxAS is highly expressed on the apical membranes of placental syncytiotrophoblasts where it is in an anatomic position to promote blood fluidity in the intervillous space. The core hypothesis of this application is that pathogenic antiphospholipid (aPL) antibodies bind to specific domains on (32-glycoprotein I, the major cofactor for aPL antibodies. These results in formation of macromolecular antibody-antigen complexes on the apical surfaces of syncytiotrophoblasts that create defects in the AnxAS anticoagulant shield and thereby promote coagulation reactions and reduce blood fluidity in the placental circulation. We have provided strong evidence for this hypothesis and have begun to develop innovative treatments that target this disease mechanism and mechanistic tests that identify resistance to AnxAS anticoagulant activity. This grant will extend the above findings with the following specific aims: 1) To investigate the effects of aPL antibodies on the AnxAS anticoagulant shield that is present on the apical membranes of placental trophoblasts. 2) To translate the findings of the first specific aim into innovative treatments targeting this disease mechanism and into mechanistic assays to diagnose the disease. These aims will be accomplished with atomic force microscopy, ellipsometry, binding studies, and coagulation enzyme studies using PL bilayers, cultured placental cells and placental villi and translational tests for AnxAS resistance. This project will be a major contribution toward elucidating a novel mechanism for pregnancy losses in a significant disease which is lacking an established pathophysiology and will open new approaches toward mechanistically-based diagnosis and treatment.