Proper autophagy is indispensable for angiogenesis during chick embryo development

People have known that autophagy plays a very important role in many physiological and pathological events. But autophagy role on embryonic angiogenesis still remains obscure. In this study, we demonstrated that Atg7, Atg8 and Beclin1 were expressed in the plexus vessels of angiogenesis at chick yolk sac membrane and chorioallantoic membrane. Interfering with autophagy with autophagy inducer or inhibitor could restrict the angiogenesis in vivo, which might be driven by the disorder of angiogenesis-related gene expressions, and also lead to embryonic hemorrhage, which was due to imperfection of endothelial cell-cell junctions including abnormal expressions of tight junction, adheren junction and desmosome genes. Using HUVECs, we revealed that cell viability and migration ability changed with the alteration of cell autophagy exposed to RAPA or 3-MA. Interestingly, tube formation assay showed that HUVECs ability of tube formation altered with the change of Atg5, Atg7 and Atg8 manipulated by the transfection of their corresponding siRNA or plasmids. Moreover, the F-actin labeled cell polarity lost and β-catenin absence in RAPA-treated cell membrane implied intracellular cytoskeleton alteration was induced by autophagy level. Taken together, our current experimental data reveal that autophagy is really involved in regulating angiogenesis during embryo development.