The Protein C Pathway in Mitigation of Radiation-Induced Endothelial and Vascular Dysfunction

项目总结/摘要 核事故或核袭击的威胁使得制定医疗对策至关重要。临床前 研究表明，血管功能障碍与慢性器官辐射损伤之间存在联系，但很少有研究表明 了解潜在的保护机制。因此，为了确定缓解目标，研究是 需要阐明参与辐射诱导的血管功能障碍和血管保护的途径。 辐射诱导的内皮功能障碍与蛋白C通路的有害改变有关。 内皮表面血栓调节蛋白（Thbd）的缺失导致活化蛋白C（APC）水平降低， 血浆中的关键成分，具有抗凝血和抗炎特性， 内皮细胞存活。我们以前已经证明重组APC是一种有效的缓解急性胰腺炎的方法。 在小鼠模型中全身照射后24小时给药时的辐射损伤。进一步探索 蛋白C通路在辐射诱导的血管功能障碍中起核心作用， APC是多器官急性和晚期辐射毒性的有效缓解剂。的体外研究 在培养中使用辐照的人内皮细胞的野生型和重组APC将确定 APC的结构特征，以及哪些内皮APC受体对于增强辐射后 内皮功能用野生型小鼠、Thbd缺陷小鼠和具有增强的Thbd的小鼠进行的体内研究。 小肠、心脏和大脑--这三个器官系统对辐射的反应是 APC的内源性水平将决定Thbd-蛋白C途径在急性和晚期的作用。 对辐射的延迟反应基因表达谱集中在从小鼠提取的内皮细胞上， 确定辐射诱导的翻译组变化以及APC对这些基因表达的影响 数据区.来自相同小鼠的血浆样品将用于鉴定指示辐射的代谢物谱 损伤和反映APC如何改变宿主反应。这样的代谢数据可能导致新的生物标志物，如 也启发了我们辐射和辐射刺激如何影响各种代谢途径。在 总之，这些研究将为Thbd-蛋白C通路的机制提供新的见解。 组件，即，APC及其内皮受体，实现内皮的放射性激动。内皮细胞研究 基因表达谱将提供深入了解哪些内皮调节系统被显着改变 被辐射所伤，被装甲运兵车救出本项目的基本知识将为以下方面提供所需的关键数据： 针对辐射诱导的血管内损伤制定了周密的对策。

PROJECT SUMMARY/ABSTRACT The threat of nuclear accidents or attacks makes it critical to develop medical countermeasures. Preclinical studies have shown a relation between vascular dysfunction and chronic organ radiation damage, but little is known about the underlying protective mechanisms. Hence, to identify targets for mitigation, research is needed to elucidate pathways involved in radiation-induced vascular dysfunction and vascular protection. Radiation-induced endothelial dysfunction is associated with detrimental alterations in the protein C pathway. Loss of endothelial surface thrombomodulin (Thbd) leads to reduced levels of activated protein C (APC), a critical component in plasma that has anticoagulant and anti-inflammatory properties and that enhances endothelial cell survival. We have previously shown that recombinant APC is an effective mitigator of acute radiation injury when administered 24 h after total-body irradiation in a mouse model. We will further explore the paradigm that the protein C pathway plays a central role in radiation-induced vascular dysfunction and that APC is an effective mitigator of both acute and late radiation toxicity in multiple organs. In vitro studies with wild-type and recombinant APC using irradiated human endothelial cells in culture will determine which structural features of APC and which endothelial APC receptors are critical for enhancing post-radiation endothelial function. In vivo studies with wild-type mice, Thbd-deficient mice, and mice with enhanced vascular responses to radiation in the small intestine, heart and brain—three organ systems critical in the endogenous levels of APC will determine the role of the Thbd–protein C pathway in both the acute and the late delayed response to radiation. Gene expression profiling focused on endothelial cells extracted from mice will identify radiation-induced changes in the translatome and the effects of APC on those gene expression profiles. Plasma samples from the same mice will be used to identify metabolite profiles indicative of radiation injury and reflective of how APC alters host responses. Such metabolic data may lead to novel biomarkers, as well as enlightening us about how radiation and radiomitigation affect various metabolic pathways. In summary, these studies will provide novel insights into mechanisms by which the Thbd–protein C pathway components, i.e., APC and its endothelial receptors, achieve endothelial radiomitigation. Studies of endothelial gene expression profiles will provide insights into which endothelial regulatory systems are significantly altered by radiation and rescued by APC. Basic knowledge from this project will provide key data required for thoughtful development of countermeasures addressing radiation-induced endovascular injury.