Anti-Coagulant and Cytoprotective activity in CCM pathogenesis

摘要 脑海绵状血管瘤 (CCM) 会发生急性和慢性出血，这是一种 是该病发病率和死亡率的主要来源。我们发现内皮细胞 在小鼠和人类 CCM 中表达的血栓调节蛋白 (TM) 水平显着升高，并且 内皮蛋白 C 受体 (EPCR)，导致内源性抗凝剂的激活 蛋白 C。我们假设 CCM 形成抗凝血管结构域并激活 蛋白 C (APC) 会导致 CCM 出血。 APC还可以发挥细胞保护作用 通过 PAR1 信号转导内皮细胞，导致内皮细胞稳定等效应 细胞与细胞的连接。事实上，APC 的这种细胞保护作用已被利用 APC 功能丧失突变体选择性地维持细胞保护活性。我们因此 假设 APC 细胞保护活性可能会限制 CCM 的发病率，就像它在 实验性中风。为了从基因上检验这一假设，我们将检查急性出血 因子 V Leiden (F5R504Q/wt) 小鼠的鼠 CCM 模型，该模型对抗凝剂具有抗性 APC的作用。作为第二种方法，我们将测试 MAPC1591（一种单克隆抗体）的效果 在 CCM 急性模型中阻断 APC 的抗凝血活性。为了测试效果 细胞保护活性，我们将检查急性 CCM 病变的发展和出血 携带选择性抵抗 APC 裂解的 PAR1 的 F2rR46Q/R46Q 小鼠。相反，我们将 检查 3K3A-APC 的影响，这是一种功能丧失的 APC 突变体，在 急性和慢性 CCM 模型中的抗凝功能。我们将利用我们的观察 短暂的缺氧或缺氧诱导因子 1A 的药物稳定作用显着 加剧围产期小鼠的急性 CCM 形成，并实现稳健的亚急性模型 表现在成年小鼠身上。这种亚急性模型同时表现出出血和含铁血黄素 沉积，将用于测试目标 1 和 2 中描述的干预措施。完成这些 目标将从机制上深入了解 TM 和 EPCR 显着增加的作用， 在 CCM 中观察到，并为出血或疾病的想法提供重要的临床前测试 进展可以通过操纵已经在治疗中的途径来影响 针对中风、败血症和血友病等疾病。

ABSTRACT Cerebral Cavernous Malformations (CCM) are subject to acute and chronic bleeding that is a major source of morbidity and mortality in this disease. We have found that endothelial cells within murine and human CCM express markedly increased levels of thrombomodulin (TM) and endothelial protein C receptor (EPCR), which lead to activation of endogenous anti-coagulant protein C. We hypothesize that CCM form an anti-coagulant vascular domain and that activated Protein C (APC) contributes to bleeding in CCM. APC can also exert a cytoprotective effect on endothelium by signaling via PAR1 resulting in, among other effects, stabilization of endothelial cell-cell junctions. Indeed, this cytoprotective effect of APC has been exploited by creation of APC loss of function mutants that selectively maintain cytoprotective activity. We thus hypothesize that APC cytoprotective activity may limit morbidity from CCM as it does in experimental stroke. To genetically test this hypothesis, we will examine the bleeding in the acute murine CCM models in Factor V Leiden (F5R504Q/wt) mice, which are resistant to the anti-coagulant effect of APC. As a second approach we will test the effect of MAPC1591, a monoclonal antibody that blocks the anti-coagulant activity of APC in acute models of CCM. To test the effects of cytoprotective activity, we will examine acute CCM lesion development and bleeding in F2rR46Q/R46Q mice bearing PAR1 that is selectively resistant to APC cleavage. Conversely, we will examine the effect of 3K3A-APC, a loss of function APC mutant that is selectively impaired in anti-coagulant function in acute and chronic CCM models. We will exploit our observation that a brief period of hypoxia or pharmacological stabilization of Hypoxia-inducible factor 1A markedly exacerbates acute CCM formation in perinatal mice and enables a robust subacute model that manifests in adult mice. This subacute model which manifests both bleeding and hemosiderin deposition, will be used to test the interventions described in aims 1 and 2. Completion of these Aims will provide mechanistic insight into the role of the marked increase of TM and EPCR that is observed in CCM and provide important preclinical tests of the idea that hemorrhage or disease progression can be influenced by manipulating pathways that are already being therapeutically targeted in diseases such as stroke, sepsis, and hemophilia.