Flt1 acts as a negative regulator of tip cell formation and branching morphogenesis in the zebrafish embryo
Flt1 acts as a negative regulator of tip cell formation and branching morphogenesis in the zebrafish embryo
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DOI：
10.1242/dev.063933
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发表时间：
2011-05-15
期刊：
影响因子：
4.6
通讯作者：
le Noble, Ferdinand
中科院分区：
文献类型：
--
作者：
Krueger, Janna;Liu, Dong;le Noble, Ferdinand
血管内皮细胞通过探索局部环境来引导血管新生萌发，如血管内皮生长因子(VEGFA)。在这里，我们提供了斑马鱼中Flt1(血管内皮生长因子受体1)功能丧失和获得的数据，表明Flt1调节尖端细胞的形成和动脉分支的形态发生。斑马鱼胚胎表达可溶性Flt1(SFlt1)和膜结合型Flt1(MFlt1)。在Tg(Flt1(BAC)：YFP)x Tg(kdrl：RAS-Cherry)(S916)胚胎中，Flt1：YFP在节段动脉芽的顶端、茎和基底细胞中表达，并与kdrl：Cherry在这些区域的表达重叠。Flt1变异体表现为尖端细胞数量增加，血管生成行为增强，节段性动脉芽超分支。这些额外的动脉分支发育成输送血液的功能性血管。为了支持Flt1细胞外血管内皮生长因子结合域的功能作用，sflt1或mflt1的过表达挽救了Flt1变体中的异常分支，而对照组的sflt1或mflt1的过表达导致了动脉短芽的丝状足的数量减少。Flt1变异体显示Notch受体和Notch下游靶基因efnb2a的表达减少，而Flt4在动脉中的异位表达，与Notch信号的丢失一致。在Flt1变异体中有条件地过表达notch1a细胞内裂解结构域可以恢复节段性动脉构型。躯干发育中的神经系统参与了Flt1的分布，而Flt1的缺失影响了神经元。因此，Flt1以Notch依赖的方式作为顶端细胞分化和分支的负调控因子发挥作用。Flt1的分布可能是微调的，涉及到与发育中的神经系统的相互作用。
Endothelial tip cells guide angiogenic sprouts by exploring the local environment for guidance cues such as vascular endothelial growth factor (VegfA). Here we present Flt1 (Vegf receptor 1) loss-and gain-of-function data in zebrafish showing that Flt1 regulates tip cell formation and arterial branching morphogenesis. Zebrafish embryos expressed soluble Flt1 (sFlt1) and membrane-bound Flt1 (mFlt1). In Tg(flt1(BAC):yfp) x Tg(kdrl:ras-cherry)(s916) embryos, flt1:yfp was expressed in tip, stalk and base cells of segmental artery sprouts and overlapped with kdrl: cherry expression in these domains. flt1 morphants showed increased tip cell numbers, enhanced angiogenic behavior and hyperbranching of segmental artery sprouts. The additional arterial branches developed into functional vessels carrying blood flow. In support of a functional role for the extracellular VEGF-binding domain of Flt1, overexpression of sflt1 or mflt1 rescued aberrant branching in flt1 morphants, and overexpression of sflt1 or mflt1 in controls resulted in short arterial sprouts with reduced numbers of filopodia. flt1 morphants showed reduced expression of Notch receptors and of the Notch downstream target efnb2a, and ectopic expression of flt4 in arteries, consistent with loss of Notch signaling. Conditional overexpression of the notch1a intracellular cleaved domain in flt1 morphants restored segmental artery patterning. The developing nervous system of the trunk contributed to the distribution of Flt1, and the loss of flt1 affected neurons. Thus, Flt1 acts in a Notch-dependent manner as a negative regulator of tip cell differentiation and branching. Flt1 distribution may be fine-tuned, involving interactions with the developing nervous system.