Poissonnier Loïc, Villain Gaëlle, Soncin Fabrice, Mattot Virginie
CNRS, Institut de Biologie de Lille, UMR8161, Université Lille-Nord de France, Lille, France.
PLoS One. 2014 Mar 4;9(3):e90455. doi: 10.1371/journal.pone.0090455. eCollection 2014.
The vasculature of the central nervous system (CNS) is composed of vascular endothelial and mural cells which interact closely with glial cells and neurons. The development of the CNS vascularisation is a unique process which requires the contribution of specific regulators in addition to the classical angiogenic factors. The egfl7 gene is mainly detected in endothelial cells during physiological and pathological angiogenesis. Egfl7 codes for a secreted protein which predominantly accumulates into the extracellular space where it controls vascular elastin deposition or the Notch pathway. Egfl7 is the host gene of the microRNA miR126 which is also expressed in endothelial cells and which plays major functions during blood vessel development. While the expression of egfl7 and that of miR126 were well described in endothelial cells during development, their pattern of expression during the establishment of the CNS vasculature is still unknown. By analysing the expression of egfl7 and miR126 during mouse retina vascularisation, we observed that while expression of miR126 is detected in all endothelia, egfl7 is initially expressed in all endothelial cells and then is progressively restricted to veins and to their neighbouring capillaries. The recruitment of mural cells around retina arteries coincides with the down-regulation of egfl7 in the arterial endothelial cells, suggesting that this recruitment could be involved in the loss of egfl7 expression in arteries. However, the expression pattern of egfl7 is similar when mural cell recruitment is prevented by the injection of a PDGFRβ blocking antibody, suggesting that vessel maturation is not responsible for egfl7 down-regulation in retinal arteries.
中枢神经系统（CNS）的脉管系统由血管内皮细胞和平滑肌细胞组成，它们与神经胶质细胞和神经元密切相互作用。CNS血管形成的发育是一个独特的过程，除了经典的血管生成因子外，还需要特定调节因子的参与。egfl7基因在生理和病理血管生成过程中主要在内皮细胞中检测到。Egfl7编码一种分泌蛋白，该蛋白主要积聚在细胞外空间，在那里它控制血管弹性蛋白的沉积或Notch信号通路。Egfl7是微小RNA miR126的宿主基因，miR126也在内皮细胞中表达，并且在血管发育过程中发挥主要功能。虽然在发育过程中egfl7和miR126在内皮细胞中的表达已有详细描述，但它们在CNS脉管系统建立过程中的表达模式仍然未知。通过分析小鼠视网膜血管生成过程中egfl7和miR126的表达，我们观察到，虽然在所有内皮细胞中都能检测到miR126的表达，但egfl7最初在所有内皮细胞中表达，然后逐渐局限于静脉及其相邻的毛细血管。视网膜动脉周围平滑肌细胞的募集与动脉内皮细胞中egfl7表达的下调同时发生，这表明这种募集可能与动脉中egfl7表达的丧失有关。然而，当通过注射PDGFRβ阻断抗体阻止平滑肌细胞募集时，egfl7的表达模式相似，这表明血管成熟与视网膜动脉中egfl7的下调无关。
