Protein modification by O-linked GlcNAc reduces angiogenesis by inhibiting Akt activity in endothelial cells
Protein modification by O-linked GlcNAc reduces angiogenesis by inhibiting Akt activity in endothelial cells
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DOI：
10.1161/atvbaha.107.159533
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发表时间：
2008-04-01
影响因子：
8.7
通讯作者：
McClain, Donald A.
中科院分区：
文献类型：
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作者：
Luo, Bai;Soesanto, Yudi;McClain, Donald A.
目的 - 通过己糖胺生物合成途径 (HBP) 的葡萄糖通量与糖尿病血管并发症的发生有关。蛋白质上的 O-连接 N-乙酰氨基葡萄糖 (O-GlcNAc) 修饰是介导 HBP 作用的主要机制。糖尿病患者的血管生成受损是众所周知的。然而，其机制尚未完全确定。在这里，我们研究了蛋白质 O-GlcNAc 修饰在血管生成中的作用。方法和结果 - 在小鼠主动脉环测定中，高脂饮食、链脲佐菌素诱导的糖尿病或体外葡萄糖胺治疗引起的 O-GlcNAc 水平升高与血管生成受损相关。在培养的人脐静脉内皮细胞和EA.hy926内皮细胞中，葡萄糖胺增加了蛋白质O-GlcNAc修饰并抑制细胞迁移和毛细血管样结构形成。相反，通过腺病毒介导的 O-GlcNAcase 过表达去除 O-GlcNAc 改善了血管生成的这些步骤。此外，高浓度的葡萄糖减少了人脐静脉内皮细胞的毛细血管样结构的形成。 Akt 被 O-GlcNAc 特异性凝集素识别，而葡萄糖胺增加了这些凝集素沉淀物中 Akt 蛋白的含量。内皮细胞中糖基化的增加与 Akt 活性的降低相平行。结论 - 这些结果表明，通过 HBP 修饰的蛋白质 O-GlcNAc 升高会损害内皮细胞中的血管生成，这可能是通过抑制 Akt 信号传导来实现的。
Objective - Glucose flux through the hexosamine biosynthesis pathway (HBP) has been implicated in the development of diabetic vascular complications. O-linked N-acetylglucosamine (O-GlcNAc) modification on protein is the major mechanism mediating the actions of the HBP. Impaired angiogenesis is well- recognized in diabetes; however, the mechanisms are not completely defined. Here, we investigated the role of protein O-GlcNAc modification in angiogenesis.Methods and Results - In a mouse aortic ring assay, elevated O-GlcNAc levels induced by high-fat diet, streptozotocin-induced diabetes, or in vitro glucosamine treatment were associated with impaired angiogenesis. In cultured human umbilical vein endothelial cells and EA.hy926 endothelial cells, glucosamine increased protein O-GlcNAc modification and inhibited cell migration and capillary-like structure formation. Conversely, removal of O-GlcNAc by adenoviral-mediated overexpression of O-GlcNAcase improved these steps of angiogenesis. Also, high concentrations of glucose reduced capillary-like structure formation of human umbilical vein endothelial cells. Akt was recognized by an O-GlcNAc specific lectin, and glucosamine increased the amounts of Akt protein in these lectin precipitates. Increased glycosylation paralleled reduced Akt activity in endothelial cells.Conclusion - These results suggest that elevated protein O-GlcNAc modification through the HBP impairs angiogenesis in endothelial cells, possibly by inhibiting Akt signaling.