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

项目总结 为了适应不断扩大的胚胎的需求，胎儿循环系统的血管必须 进行广泛的形态重塑，同时支持原有的组织。机械式 由血液动力产生的刺激是这一过程的关键调节器，驱动适应性反应。 到血流，如血管融合、增宽或消退。 在此，我们建议进行实验，以确定早期血管如何对血液变化做出反应。 流。我们的假设是，Flk1/ERK/DLL4/Notch信号轴的差异激活创建了一个 有能力对血流做出反应的内皮细胞亚群，导致血管内皮细胞的定向迁移和扩张 卵黄动脉。我们集结了一支优秀的调查团队，以及新的技术， 小鼠模型和方法在三个具体目标上检验这一假说：1.使用功能丧失和功能获得 Flk1/ERK/DLL4/Notch信号模型用于确定血管内皮细胞迁移的差异 改建。2.使用实时ERK生物传感器确定迁移的内皮细胞是否响应 血流上调ERK活性，如果改变ERK信号，或调节血流，则会影响细胞迁移。 3.采用单细胞RNA测序方法确定VA中是否存在特定的高细胞群 动脉基因表达和极化和亲迁移基因水平升高。转录数据 将补充动态的3D成像数据，使我们能够揭示 专门的ECs，否则将通过种群水平的研究而丢失(例如通过批量RNA-seq)和 这无疑将推动未来对血流动力信号和胚胎中内皮细胞迁移的新的研究。

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.