Aquaporins调控血管新生过程中管腔形成的机制研究

The formation of vascular lumens by endothelial cells (EC) in the emerging vascular sprout is a critical step of angiogenesis. To date, our understanding of how the lumens of endothelial cell tubular networks are formed and maintained in blood vessels is still in its infancy. The major questions in vascular tubulogenesis remain to be answered. In our preliminary work, we found that aqp1a.1and aqp8a.1, the members of Aquaporins (Aqp) gene family, are highly enriched in the developing ECs of zebrafish embryos. Aqp1a.1/aqp8a.1 loss of function resulted in the lumen formation defects of intersegmental vessels (ISVs), dorsal aorta (DA) and posterior cardinal vein (PCV) in zebrafish. In contrast, the overexpression of aqp1a.1/aqp8a.1 in ECs significantly increased the diameter of ISVs, DA and PCV. Based on these observations, we hypothesized that Aquaporins are a sort of novel and crucial regulators of blood vessel lumen formation. In current project, we plan to investigate the cellular and molecular mechanisms of that aqp1a.1 and aqp8a.1 regulates vascular tubulogenesis on primary cultured ECs, human embryonic stems-derived ECs and several transgenic/gene knockout zebrafish models, using the combination of different techniques, including confocal microscopic live imaging and transcriptome sequencing.

在血管新生的起始阶段，通过内皮细胞形成血管管腔(vascular lumen)的过程是血管新生的关键步骤。但是到目前为止，对血管管腔形成的认识还处于初级阶段，血管腔化(tubulogenesis)过程中的一些关键问题还有待进一步的回答。我们前期的研究发现水孔通道（Aquaporins， Aqp）基因aqp1a.1和aqp8a.1特异的表达在发育中的斑马鱼血管内皮细胞。aqp1a.1和aqp8a.1分别敲除造成胚胎发育过程中血管管腔的形成缺陷；而过表达则导致斑马鱼节间血管和主动脉、主静脉直径显著变大，促进血管腔化。据此我们推断：aqp1a.1和aqp8a.1为血管腔化的重要的调控因子。本项目拟通过结合激光共聚焦活体成像、转录组测序等多种技术，利用原代内皮细胞和人胚胎干细胞定向分化内皮细胞、特别是多种转基因和基因敲除斑马鱼模型来研究aqp1a.1和aqp8a.1调控血管腔化的细胞和分子机制。

在血管新生的起始阶段，通过内皮细胞形成血管管腔(vascular lumen)的过程是血管新生的关键步骤。但是到目前为止，对血管管腔形成的认识还处于初级阶段，血管腔化(tubulog enesis)过程中的一些关键问题还有待进一步的回答。本项目拟通过结合激光共聚焦活体成像、转录组测序等多种技术，利用原代内皮细胞和人胚胎干细胞定向分化内皮细胞、特别是多种转基因和基因敲除斑马鱼模型来研究aqp1a.1和aqp8a.1调控血管腔化的细胞和分子机制。我们观察到高糖处理的斑马鱼胚胎血管直径减少和灌注损害。两种水通道蛋白(aqp1a.1和aqp8a.1)在高血糖状态下显著下调，在血管系统内皮细胞(ECs)中时空富集。在高血糖斑马鱼模型中，aqp1a.1或aqp8a.1突变后ISV管腔化异常，而过表达则可以促进斑马鱼血管直径的增大；上调aqp1a.1可挽救高糖处理引起的血管缺损。此外，aqp1a.1或aqp8a.1定位于内皮细胞的液泡中，这是管腔化所必需的。最后，我们发现在糖尿病人视网膜样本和高糖处理的人视网膜微血管内皮细胞中，AQP1的表达也下调。综上所述，富含水通道蛋白的内皮细胞液泡膜在发育和病理性血管管腔化过程中发挥作用，是基因治疗糖尿病相关血管管腔化缺陷的潜在靶点。

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