Reduction of Annexin A5 in Antipholipid Pregnancy Loss

描述（由申请方提供）：反复妊娠丢失是抗磷脂综合征（APS）的标志，这是一种复杂的主要高凝障碍，目前尚无确定的机制，可通过现象学替代试验进行诊断。APS与一系列血栓性并发症相关，包括复发性流产、中风、深静脉血栓形成和肺栓塞。胎盘抗凝蛋白膜联蛋白A5（AnxAS）是一种有效的磷脂（PL）结合蛋白，其在含有阴离子PL的膜上形成二维抗凝晶体屏蔽。AnxAS在胎盘合体滋养细胞的顶膜上高度表达，在那里它处于解剖位置以促进绒毛间隙中的血液流动性。本申请的核心假设是致病性抗磷脂（aPL）抗体结合β 2-糖蛋白I上的特异性结构域，β 2-糖蛋白I是aPL抗体的主要辅因子。这些导致在合体滋养层的顶端表面上形成大分子抗体-抗原复合物，其在AnxAS抗凝屏障中产生缺陷，从而促进 凝血反应，降低胎盘循环中的血液流动性。我们已经为这一假设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，以及确定对AnxAS抗凝活性耐药性的机制测试。这笔赠款将扩大上述调查结果，具体目标如下： 1)为了研究aPL抗体对存在于 胎盘滋养层的顶端膜。 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方法 机制和机制分析来诊断疾病。这些目标将通过原子力显微镜、椭圆偏振法、结合研究和使用PL双层、培养的胎盘细胞和胎盘绒毛的凝固酶研究以及AnxAS抗性的翻译试验来实现。 该项目将是对阐明妊娠损失的新机制的重大贡献 在一种缺乏既定病理生理学的重大疾病中， 以机械为基础的诊断和治疗方法。

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.