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Arterioscler Thromb Vasc Biol. 2008 Apr;28(4):651-7. doi: 10.1161/ATVBAHA.107.159533. Epub 2008 Jan 3.

Protein modification by O-linked GlcNAc reduces angiogenesis by inhibiting Akt activity in endothelial cells.

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  • 1Division of Endocrinology, University of Utah, Salt Lake City, UT 84132, USA.

Abstract

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.

CONCLUSIONS:

These results suggest that elevated protein O-GlcNAc modification through the HBP impairs angiogenesis in endothelial cells, possibly by inhibiting Akt signaling.

Comment in

PMID:
18174452
[PubMed - indexed for MEDLINE]
PMCID:
PMC2734484
Free PMC Article
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