GAA deficiency promotes angiogenesis through upregulation of Rac1 induced by autophagy disorder
GAA deficiency promotes angiogenesis through upregulation of Rac1 induced by autophagy disorder
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DOI：
10.1016/j.bbamcr.2021.118969
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发表时间：
2021-01-30
影响因子：
5.1
通讯作者：
Chen, Sun
中科院分区：
文献类型：
--
作者：
Li, Zhuoyan;Li, Baolei;Chen, Sun
血管生成，即从已有的血管形成新的血管，对脊椎动物的发育和成年体内平衡至关重要。酸性α-葡糖苷酶（GAA）是参与糖原的溶酶体分解的糖苷水解酶。我们前期的研究表明GAA在小鼠肺静脉中高表达。虽然GAA是否参与血管生成仍然在很大程度上是未知的，因此，我们在体内和体外进行敲除实验和内皮细胞功能实验，以澄清这一关注点。结果表明，GAA在斑马鱼胚胎发育过程中广泛表达，且表达水平不同，GAA变体在斑马鱼胚胎发育后期表现出ISV过度的血管生成。GAA基因敲减后的HUVECs迁移能力增强，管腔形成能力增强，这是由于细胞边缘形成大的片状伪足样突起所致。通过分析自噬流，我们发现自噬紊乱是GAA敲低诱导过度血管生成的机制。自噬通量的阻断导致Rac 1（一种小的GTbR）的上调，后者促进了斑马鱼的过度出芽，增强了HUVEC的血管生成行为。此外，转录因子E3（自噬的主要调节因子）的过表达挽救了RAC 1的上调，并增强了GAA敲低HUVEC的血管生成功能。此外，Rac 1的抑制部分恢复了GAA敲低HUVEC中增强的血管生成功能。综上所述，我们的研究首次报道了GAA在血管生成中的新功能，其通过自噬障碍诱导的Rac 1上调介导。
Angiogenesis, the formation of new blood vessels from pre-existing ones, is vital for vertebrate development and adult homeostasis. Acid alpha-glucosidase (GAA) is a glycoside hydrolase involved in the lysosomal breakdown of glycogen. Our previous study showed that GAA was highly expressed in mouse pulmonary veins. While whether GAA was involved in angiogenesis remained largely unknown, thus, we performed knockdown experiments both in vivo and in vitro and endothelial cell function experiments to clarify this concern point. We identified that GAA expressed widely at different levels during zebrafish embryonic development and GAA morphants showed excessive angiogenesis of ISV at later stage. In GAA knockdown HUVECs, the migration and tube formation capacity were increased, resulted from the formation of large lamellipodia-like protrusions at the edge of cells. By analyzing autophagic flux, we found that autophagy disorder was the mechanism of GAA knockdown-induced excessive angiogenesis. The block of autophagic flux caused upregulation of Rac1, a small GTPase, and the latter promoted excessive sprouts in zebrafish and enhanced angiogenic behavior in HUVECs. In addition, overexpression of transcription factor E3, a master regulator of autophagy, rescued upregulation of RAC1 and enhanced angiogenic function in GAA-knockdown HUVECs. Also, inhibition of Rac1 partly restored enhanced angiogenic function in GAA-knockdown HUVECs. Taken together, our study firstly reported a novel function of GAA in angiogenesis which is mediated by upregulation of Rac1 induced by autophagy disorder.