Moyon D, Pardanaud L, Yuan L, Bréant C, Eichmann A
Institut d'Embryologie Cellulaire et Moléculaire CNRS FRE 2160, 49bis, Avenue de la Belle Gabrielle, Nogent-sur-Marne Cedex 94736, France.
Development. 2001 Sep;128(17):3359-70. doi: 10.1242/dev.128.17.3359.
Remodeling of the primary vascular system of the embryo into arteries and veins has long been thought to depend largely on the influence of hemodynamic forces. This view was recently challenged by the discovery of several molecules specifically expressed by arterial or venous endothelial cells. We here analysed the expression of neuropilin-1 and TIE2, two transmembrane receptors known to play a role in vascular development. In birds, neuropilin-1 was expressed by arterial endothelium and wall cells, but absent from veins. TIE2 was strongly expressed in embryonic veins, but only weakly transcribed in most arteries. To examine whether endothelial cells are committed to an arterial or venous fate once they express these specific receptors, we constructed quail-chick chimeras. The dorsal aorta, carotid artery and the cardinal and jugular veins were isolated together with the vessel wall from quail embryos between embryonic day 2 to 15 and grafted into the coelom of chick hosts. Until embryonic day 7, all grafts yielded endothelial cells that colonized both host arteries and veins. After embryonic day 7, endothelial plasticity was progressively lost and from embryonic day 11 grafts of arteries yielded endothelial cells that colonized only chick arteries and rarely reached the host veins, while grafts of jugular veins colonized mainly host veins. When isolated from the vessel wall, quail aortic endothelial cells from embryonic day 11 embryos were able to colonize both host arteries and veins. Our results show that despite the expression of arterial or venous markers the endothelium remains plastic with regard to arterial-venous differentiation until late in embryonic development and point to a role for the vessel wall in endothelial plasticity and vessel identity.
长期以来，人们一直认为胚胎初级血管系统重塑为动脉和静脉在很大程度上取决于血流动力学力的影响。最近，这一观点受到了挑战，因为发现了几种由动脉或静脉内皮细胞特异性表达的分子。我们在此分析了神经纤毛蛋白-1和TIE2这两种已知在血管发育中起作用的跨膜受体的表达情况。在鸟类中，神经纤毛蛋白-1由动脉内皮和壁细胞表达，但静脉中不存在。TIE2在胚胎静脉中强烈表达，但在大多数动脉中仅微弱转录。为了研究内皮细胞一旦表达这些特异性受体是否就注定了动脉或静脉命运，我们构建了鹌鹑-鸡嵌合体。从胚胎第2天到第15天的鹌鹑胚胎中分离出背主动脉、颈动脉以及主静脉和颈静脉连同血管壁，移植到鸡宿主的体腔中。直到胚胎第7天，所有移植组织产生的内皮细胞都能在宿主的动脉和静脉中定植。胚胎第7天之后，内皮可塑性逐渐丧失，从胚胎第11天起，动脉移植组织产生的内皮细胞仅能在鸡的动脉中定植，很少能到达宿主静脉，而颈静脉移植组织主要定植在宿主静脉中。当从血管壁分离时，来自胚胎第11天胚胎的鹌鹑主动脉内皮细胞能够在宿主的动脉和静脉中定植。我们的结果表明，尽管存在动脉或静脉标志物的表达，但在内皮细胞-静脉分化方面，内皮在胚胎发育后期之前仍保持可塑性，并表明血管壁在内皮可塑性和血管特性方面发挥作用。
