Platelet-mediated mechanisms of placental and systemic hypercoagulability in preeclampsia

项目总结/摘要 先兆子痫（PE）仍然是一个重要的临床和公共卫生负担，影响所有妊娠的3- 5 这是全世界范围内的一个主要疾病，也是孕产妇和围产期发病率和死亡率的主要原因。目前尚无 除分娩外，PE的有效治疗。虽然其病因尚不完全清楚，但令人信服的证据表明， 胎盘缺氧/缺血是一个关键的起始事件，触发释放抗血管生成因子， 母体循环，如可溶性fms样酪氨酸激酶-1（sFLT-1）和内皮糖蛋白（sEng）。这些胎盘 这些因素导致全身血管功能障碍并最终导致PE的临床症状。此外，PE是 明确的高凝状态，与胎盘血栓形成以及增加的风险 妊娠期间和妊娠后的血栓形成事件。高凝状态可能会导致过度的胎盘 疾病和全身血管功能障碍。虽然促凝血因子的表达增加， 血小板活性沿着抗凝活性的降低与这种血栓形成前倾向有关， PE中高凝状态的确切机制仍有待充分阐明。细胞外 线粒体DNA（mtDNA），一种缺氧和/或损伤后释放的损伤相关分子模式， 已知组织直接激活血小板，通过它们的活性引发活性氧物质的过度产生。 线粒体，这反过来又导致细胞凋亡和从血小板释放额外的mtDNA。这个这个信号 正向循环导致血小板活化和高凝状态升级，最终导致血栓形成， 从mtDNA释放的起始位点开始虽然PE患者的胎盘和母体mtDNA水平升高， 在PE期间，它作为胎盘和体循环中高凝状态的介质的作用从未被 研究了此外，循环中的mtDNA可以通过DNase I处理直接耗尽，这已经被证明是可行的。 抑制体外和体内血小板活化和聚集。然而，DNA酶I从未被探索为 治疗PE的方法为了解决这一知识缺口，我们建议研究mtDNA是否作为一个驱动程序， PE期间胎盘和体循环中的高凝状态，以及这种影响是否可以减轻 使用严重PE的大鼠sFLT-1/sEng模型通过DNA酶I治疗。与重度先兆子痫患者相似， 向妊娠大鼠中长期输注sFLT-1和sEng可促进胎盘病理学、高血压、降低 血小板计数和终末器官损伤平行的离体研究将确定sFLT-1、sEng和 胎盘mtDNA引起血小板活化、线粒体功能障碍和聚集。因此，通过应用 整合的新方法，临床相关的PE模型和先进的方法，我们将测试 线粒体DNA介导血小板活化，线粒体功能障碍，高凝状态， 严重PE中的血管功能障碍，并且该途径通过DNA酶I治疗得到改善。结果 这些突破性的研究产生的新方法可以通过确定一种新的 这类以mtDNA为靶点的抗血栓药物对其他高凝状态具有潜在的广泛适用性。

PROJECT SUMMARY/ABSTRACT Preeclampsia (PE) remains a significant clinical and public health burden affecting 3-5% of all pregnancies worldwide, and is a leading cause of maternal and perinatal morbidity and mortality. Currently, there is no effective therapy for PE other than delivery. While its etiology is not fully clear, compelling evidence demonstrates that placental hypoxia/ischemia is a key initiating event that triggers the release of anti-angiogenic factors into maternal circulation, such as soluble fms-like tyrosine kinase-1 (sFLT-1) and endoglin (sEng). These placental factors cause systemic vascular dysfunction and ultimately the clinical symptoms of PE. Furthermore, PE is a well-established hypercoagulable state, associated with placental thrombosis as well as increased risk for thrombotic events during and after pregnancy. Hypercoagulability could contribute to exaggerated placental disease and systemic vascular dysfunction in PE. Although increased expression of procoagulant factors and platelet activity along with decreased anticoagulant activity have been implicated in this prothrombotic tendency, the precise mechanism underlying hypercoagulability in PE remain to be fully elucidated. Extracellular mitochondrial DNA (mtDNA), a damage-associated molecular pattern released from hypoxic and/or injured tissue, is known to directly activate platelets, triggering reactive oxygen species overproduction by their mitochondria, which in turn leads to apoptosis and release of additional mtDNA from platelets. This this feed- forward cycle results in escalating platelet activation and hypercoagulability that culminate in thrombosis remote from the initial site of mtDNA release. While placental and maternal mtDNA levels are elevated in PE patients, its role as a mediator of hypercoagulability in the placental and systemic circulation during PE has never been investigated. Moreover, circulating mtDNA can be directly depleted by DNase I treatment, which has been shown to inhibit in vitro and in vivo platelet activation and aggregation. However, DNase I has never been explored as a therapy for PE. To address this knowledge gap, we propose to examine whether mtDNA acts as a driver of hypercoagulability in the placental and systemic circulation during PE, and whether this effect can be mitigated by DNase I treatment using the rat sFLT-1/sEng model of severe PE. Similar to severe preeclamptic patients, the chronic sFLT-1 and sEng infusion into pregnant rats promotes placental pathology, hypertension, reduced platelet counts, and end-organ damage. Parallel ex vivo studies will determine whether sFLT-1, sEng, and placental mtDNA cause platelet activation, mitochondrial dysfunction, and aggregation. Thus, by applying integrative novel approaches, clinically relevant models of PE, and advanced methodologies, we will test the central hypothesis that mtDNA mediates platelet activation, mitochondrial dysfunction, hypercoagulability, and vascular dysfunction in severe PE, and that this pathway is ameliorated by DNase I treatment. Findings generated by these groundbreaking studies could revolutionize the standard of care for PE by identifying a novel class of mtDNA-targeted antithrombotic agents with potential wide applicability to other hypercoagulable states.