Huang Lvzhen, Yu Wenzhen, Li Xiaoxin, Niu Lanjun, Li Kai, Li Juan
Department of Ophthalmology, Peking University People's Hospital, Beijing, China.
Exp Eye Res. 2009 Mar;88(3):583-8. doi: 10.1016/j.exer.2008.11.016. Epub 2008 Dec 3.
Two members of the roundabout (Robo) family, Robo1 and Robo4, serve as neuronal guidance receptors. During neurogenesis, Robo1 and Robo4 participate in axonal guidance by mediating a repulsive signal. It has been reported that Robo4 is mainly expressed in the vasculature and that Robo1 is expressed both in neural and non-neural tissues. However, the roles of these Robo proteins in the mammalian vasculature are still unclear. In this current study, the expression patterns of Robo1 and Robo4 in the retinal vasculature were determined using C57BL/6J mice at postnatal days (P) 1, P3, P5, P7, P9, P12, P14, P17, P21 and adult mice (1month). We found that Robo4 was expressed not only in the retinal vessels but also in the retinal ganglion cell and photoreceptor layers during retinal development. Robo4 expression peaked at P3 and P9, which suggest that Robo4 may function in stabilizing the retinal vasculature. Robo1 expression was observed in the retina neuronal cells and vessels. Both Robo1 mRNA and protein expression showed a typical expression pattern, which related to Robo1's roles in the different stages of retinal vascular development in the murine retina. Robo1 displayed high expression levels at P1 (correlated with superficial vascular plexus formation) and P7 (correlated with deep vascular plexus formation). The high levels of Robo1 during these two well-defined phases of retinal capillary plexus formation indicate that Robo1 is likely to play a part in retinal neovascularization.
“转向”（Robo）家族的两个成员Robo1和Robo4作为神经元导向受体发挥作用。在神经发生过程中，Robo1和Robo4通过介导排斥信号参与轴突导向。据报道，Robo4主要在脉管系统中表达，而Robo1在神经组织和非神经组织中均有表达。然而，这些Robo蛋白在哺乳动物脉管系统中的作用仍不清楚。在本研究中，使用出生后第1天（P1）、P3、P5、P7、P9、P12、P14、P17、P21的C57BL/6J小鼠以及成年小鼠（1个月），确定了Robo1和Robo4在视网膜脉管系统中的表达模式。我们发现，在视网膜发育过程中，Robo4不仅在视网膜血管中表达，还在视网膜神经节细胞层和光感受器层中表达。Robo4的表达在P3和P9时达到峰值，这表明Robo4可能在稳定视网膜脉管系统中发挥作用。在视网膜神经元细胞和血管中观察到了Robo1的表达。Robo1的mRNA和蛋白表达均呈现出典型的表达模式，这与Robo1在小鼠视网膜血管发育不同阶段的作用相关。Robo1在P1（与浅表血管丛形成相关）和P7（与深部血管丛形成相关）时表达水平较高。在视网膜毛细血管丛形成的这两个明确阶段中Robo1的高水平表达表明，Robo1可能在视网膜新生血管形成中发挥作用。
