Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou, 510632, China.
Chinese Medicine College, Jinan University, Guangzhou, 510632, China.
Mol Neurobiol. 2018 Apr;55(4):3523-3536. doi: 10.1007/s12035-017-0583-6. Epub 2017 May 16.
Autophagy plays a very important role in numerous physiological and pathological events. However, it still remains unclear whether Atg7-induced autophagy is involved in the regulation of neural crest cell production. In this study, we found the co-location of Atg7 and Pax7 neural crest cells in early chick embryo development. Upregulation of Atg7 with unilateral transfection of full-length Atg7 increased Pax7 and HNK-1 cephalic and trunk neural crest cell numbers compared to either Control-GFP transfection or opposite neural tubes, suggesting that Atg7 over-expression in neural tubes could enhance the production of neural crest cells. BMP4 in situ hybridization and p-Smad1/5/8 immunofluorescent staining demonstrated that upregulation of Atg7 in neural tubes suppressed the BMP4/Smad signaling, which is considered to promote the delamination of neural crest cells. Interestingly, upregulation of Atg7 in neural tubes could significantly accelerate cell progression into the S phase, implying that Atg7 modulates cell cycle progression. However, β-catenin expression was not significantly altered. Finally, we demonstrated that upregulation of the Atg7 gene could activate autophagy as did Atg8. We have also observed that similar phenotypes, such as more HNK-1 neural crest cells in the unilateral Atg8 transfection side of neural tubes, and the transfection with full-length Atg8-GFP certainly promote the numbers of BrdU neural crest cells in comparison to the GFP control. Taken together, we reveal that Atg7-induced autophagy is involved in regulating the production of neural crest cells in early chick embryos through the modification of the cell cycle.
自噬在许多生理和病理事件中起着非常重要的作用。然而，目前尚不清楚 Atg7 诱导的自噬是否参与神经嵴细胞产生的调节。在这项研究中，我们发现 Atg7 与 Pax7 神经嵴细胞在早期鸡胚发育中存在共定位。与对照 GFP 转染或相反的神经管相比，单侧全长 Atg7 转染上调 Atg7 增加了 Pax7 和 HNK-1 头和躯干神经嵴细胞的数量，表明神经管中 Atg7 的过表达可以增强神经嵴细胞的产生。BMP4 原位杂交和 p-Smad1/5/8 免疫荧光染色表明，神经管中 Atg7 的上调抑制了 BMP4/Smad 信号，该信号被认为促进了神经嵴细胞的分层。有趣的是，神经管中 Atg7 的上调可以显著加速细胞进入 S 期，这意味着 Atg7 调节细胞周期进程。然而，β-连环蛋白的表达没有明显改变。最后，我们证明上调 Atg7 基因可以像 Atg8 一样激活自噬。我们还观察到，类似的表型，如神经管单侧 Atg8 转染侧的更多 HNK-1 神经嵴细胞，以及全长 Atg8-GFP 的转染，与 GFP 对照相比，肯定会促进 BrdU 神经嵴细胞的数量。总之，我们揭示了 Atg7 诱导的自噬通过细胞周期的修饰参与调节早期鸡胚神经嵴细胞的产生。
