Endothelial cell autonomous mechanisms of blood vessel diameter control

摘要 血管对于将营养物质和氧气分配到我们身体的各个部位都很重要。一种等级制度 不同大小的血管的组织是其功能的关键。几种疾病会影响血液 血管的拓扑和直径，导致人类的血管畸形。此前的报道表明， 血管直径的增加可由血管内皮细胞数量的增加引起，血管内皮细胞 血管的内层。我们在斑马鱼胚胎中建立了一种成像方法，使我们能够准确地 分析胚胎发育期间内皮细胞的数量以及它们的形状和大小。 令人惊讶的是，我们发现最初内皮细胞的形状和大小对血管更重要 血管直径控制比血管内皮细胞数量多，血管内皮细胞数量仅在血管后期增加 畸形机构。重要的是，我们还发现血管内皮细胞的形状和大小在 导致血管畸形的几种不同基因的突变。然而，到目前为止，还不知道这些 基因影响细胞的形状和大小，以及这将如何影响血管直径。这项提案的目的是 通过分析影响细胞形状和大小的细胞和分子成分来解决这个问题。在……里面 目的1我们将研究细胞骨架及其收缩特性如何影响细胞尺寸以及如何 这可能会对血管直径产生反馈。我们还将调查改变细胞骨架和 因此，内皮细胞的收缩能力可以挽救血管畸形。在目标2中，我们计划审问 内皮细胞极性对血管内径的影响。内皮细胞有一个顶端，面向血液 管腔和基底侧膜域。目前，我们还不知道突变是如何导致血管 畸形改变了心尖-基底部的极性，以及这些改变将如何影响血管直径。我们会 通过检测不同斑马鱼突变体的顶端和基侧极性来测试这些可能性 血管畸形。我们还将研究改变心尖-基底外侧极性对内皮细胞的影响 这些突变体中的细胞形状和大小。最终，我们的目标是通过正常化来逆转血管畸形 心尖-基底侧的极性和内皮细胞的收缩能力，从而增加之前的内皮细胞的形状 内皮细胞的数量。

Abstract Blood vessels are important for the distribution of nutrients and oxygen to all parts of our bodies. A hierarchical organization of differently sized blood vessels is key for their functionality. Several diseases can affect blood vessel topologies and diameters, leading to vascular malformations in humans. Previous reports suggested that increases in blood vessel diameters can be caused by increases in endothelial cell numbers, the cells of the blood vessels’ inner lining. We established an imaging approach in zebrafish embryos that allows us to precisely analyze endothelial cell numbers in addition to their shapes and sizes during embryonic development. Surprisingly, we found that initially the shapes and sizes of endothelial cells were more critical for blood vessel diameter control than their numbers and that endothelial cell numbers increased only at later stages of vascular malformation establishment. Importantly, we also found that endothelial shapes and sizes were affected in mutants of several different genes causing vascular malformations. However, to date it is not known how these genes affect cell shapes and sizes and how this would impact blood vessel diameters. The aims in this proposal address this question by analyzing the cellular and molecular components influencing cell shapes and sizes. In aim 1 we will investigate how the cytoskeleton and its contractile properties affect cellular dimensions and how this might feedback on blood vessel diameters. We will also investigate whether changing the cytoskeleton and hence endothelial cell contractility can rescue vascular malformations. In aim 2 we plan to interrogate the influence of endothelial cell polarity on blood vessel diameters. Endothelial cells have an apical, facing the blood vessel lumen, and a basolateral membrane domain. At present, we do not know how mutations causing vascular malformations change apical-basal polarity and how these changes would affect blood vessel diameters. We will test for these possibilities by examining apical and basolateral polarity in different zebrafish mutants that develop vascular malformations. We will also investigate how changing apical-basolateral polarity will affect endothelial cell shapes and sizes in these mutants. Ultimately, we aim to reverse vascular malformations through normalizing apical-basolateral polarity and endothelial cell contractility and thereby endothelial cell shapes prior to increases in endothelial cell numbers.