Dynamic regulation of embryonic endothelial cell migration in response to hemodynamic force

项目摘要 为了适应不断膨胀的胚胎的需要，胎儿循环系统的血管必须 经历广泛的形态重塑，同时支持预先存在的组织。机械 由血液动力学力产生的刺激是这一过程的关键调节器，驱动适应性反应 对血流的影响，例如血管融合、增宽或消退。 在此，我们提出实验，以确定如何早期血管重塑，以应对血液中的变化， 流我们的假设是Flk1/ERK/Dll4/Notch信号转导轴的差异激活产生了一个信号转导通路。 有能力对血流作出反应的EC亚群，导致定向迁移和扩张， 卵黄动脉我们已经组建了一支优秀的调查团队，以及新颖的技术， 小鼠模型和方法在三个特定目的中测试该假设：1.使用功能丧失和功能获得 Flk1/ERK/Dll4/Notch信号传导模型，以确定血管内皮细胞（EC）迁移过程中的差异 重塑2.使用实时ERK生物传感器来确定是否EC迁移响应的变化， 血流上调ERK活性，并且如果改变ERK信号传导或调节血流，则影响细胞迁移。 3.采用单细胞RNA测序来确定VA中是否存在具有高表达的特定细胞群。 动脉基因表达以及极化和促迁移基因水平升高。转录数据 将补充动态，三维成像数据，使我们能够揭示网络所需的因素， - 通过群体水平的研究（例如，通过批量RNA-seq）可能会丢失的专门EC，以及 毫无疑问，这将促进对胚胎中血流动力学信号和EC迁移的新的未来研究。

PROJECT SUMMARY To accommodate the demands of the constantly expanding embryo, vessels of the fetal circulatory system must undergo extensive morphological remodeling while simultaneously supporting pre-existing tissues. Mechanical stimuli, generated by the hemodynamic force, are critical regulators of this process, driving adaptive responses to blood flow such as vessel fusion, widening, or regression. Herein, we propose experiments to determine how early vessels remodel in response to changes in blood flow. Our hypothesis is that differential activation of a Flk1/ERK/Dll4/Notch signaling axis creates a subset of ECs competent to respond to blood flow, resulting in the directed migration and expansion of the vitelline artery. We have assembled an outstanding team of investigators, as well as novel technologies, mouse models and methods to test this hypothesis in three specific aims: 1. Use loss- and gain-of-function models of Flk1/ERK/Dll4/Notch signaling to define differences in endothelial cell (EC) migration during vessel remodeling. 2. Use a real-time ERK biosensor to determine whether ECs that migrate in response to changes in blood flow upregulate ERK activity and if altering ERK signaling, or modulating blood flow, affects cell migration. 3. Employ single cell RNA-sequencing to determine if a specific population of cells exists in the VA with high arterial gene expression and elevated levels of polarization and pro-migratory genes. The transcriptional data will complement the dynamic, 3D imaging data, allowing us to reveal the network of factors required in specialized ECs that would otherwise be lost through studies at a population level (e.g. via bulk RNA-seq) and will no doubt prompt novel future investigation into hemodynamic force signaling and EC migration in the embryo.