Embryonic origins of endothelial heterogeneity

项目摘要 内皮异质性是成熟循环系统的一个定义性特征。内皮 排列在毛细血管床或其他小口径血管上的细胞具有不同的表型和分子生物学特性， 与其在不同解剖位置的各种功能相关的签名。在较大的血管中， 动脉和静脉内皮细胞之间存在明显的分子和表型差异。 在所有这些情况下，内皮分化对于血管内皮细胞的正常生理功能是必不可少的。 循环系统重要的是，内皮异质性可能对该部位产生重大影响， 血管疾病的严重程度。因此，更好地了解内皮细胞类型是如何 决定是非常重要的。在过去的15年里，我们一直把斑马鱼作为一个模型系统， 探讨胚胎发育过程中血管形态发生和模式形成的基本机制 发展我们的努力揭示了血管如何形成的新见解， 强调了内皮分化在这一过程中的重要性。重要的是，我们发现 内皮细胞分化是血管形成的基本步骤， 组装件.然而，内皮细胞特性的发育起源和信号通路 驱动力差异在很大程度上是未知的。在这里提出的研究中，我们将应用一些 传统的发育生物学方法加上尖端的分子技术， 定义了胚胎发育过程中内皮个体发育的层次。通过Cre/lox血统 追踪我们将确定何时何地建立内皮细胞类型。同时，我们将 在多个发育阶段对内皮祖细胞进行单细胞RNA测序， 鉴定定义内皮亚型的转录组特征。与此同时，努力查明 增强子元件侧翼亚型特异性基因将有助于我们的知识，转录 调控途径和上游信号驱动分化。最后，我们将继续 研究内皮分化和血管形态发生之间的联系， 使用通过基因组产生敲除斑马鱼模型来询问亚型特异性基因 编辑.总之，我们的努力将确定发展内皮等级，并使我们能够 确定负责内皮异质性的基本信号通路。

PROJECT SUMMARY Endothelial heterogeneity is a defining characteristic of the mature circulatory system. Endothelial cells that line capillary beds or other small caliber vessels have distinct phenotypes and molecular signatures that relate to their various functions in different anatomical locations. In larger vessels, there are clear molecular and phenotypic differences between arterial and venous endothelial cells. In all of these cases, endothelial differentiation is essential for normal physiological function of the circulatory system. Importantly, endothelial heterogeneity can have a major influence on the site and severity of vascular disease. Thus, a better understanding of how endothelial cell types are determined is highly relevant. For the past 15 years, we have used the zebrafish as a model system to investigate basic mechanisms of vascular morphogenesis and patterning during embryonic development. Our efforts have revealed new insights into how blood vessels are formed and underscore the importance of endothelial differentiation in this process. Importantly, we have found that endothelial cell differentiation is a primary step that is essential for blood vessel formation and assembly. However, the developmental origins of endothelial identities and the signaling pathways that drive differentiation are largely unknown. In the studies proposed here, we will apply a number of traditional developmental biology approaches coupled with cutting-edge molecular techniques to define the hierarchy of endothelial ontogeny during embryonic development. Through Cre/lox lineage tracing we will identify where and when endothelial cell types are established. In parallel, we will apply single cell RNA sequencing on endothelial progenitors at multiple developmental stages to identify transcriptome signatures that define endothelial subtypes. At the same time, efforts to identify enhancer elements flanking subtype-specific genes will contribute to our knowledge of transcriptional regulatory pathways and upstream signals that drive differentiation. Finally, we will continue to investigate the link between endothelial differentiation and vascular morphogenesis through functional interrogation of subtype specific genes using knockout zebrafish models generated through genome editing. Together, our efforts will define the developmental endothelial hierarchy and allow us to identify essential signaling pathways responsible for endothelial heterogeneity.