Biological and Pharmaceutical Bulletin
Online ISSN : 1347-5215
Print ISSN : 0918-6158
ISSN-L : 0918-6158
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Protein O-N-Acetylglucosaminylation Modulates Promoter Activities of Cyclic AMP Response Element and Activator Protein 1 and Enhances E-Selectin Expression on HuH-7 Human Hepatoma Cells
Yutaro AzumaKana MiuraKoji HigaiKojiro Matsumoto
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2007 Volume 30 Issue 12 Pages 2284-2289

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Abstract

High glucose accelerates O-N-acetylglucosaminylation (O-GlcNAcylation) of proteins and causes diabetic complications. In the present study, we found that treatment of HuH-7 human hepatoma cells with high glucose or the protein O-N-acetylglucosaminidase (O-GlcNAcase) inhibitor O-(2-acetoamide-2-deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate (PUGNAc) increased the cell surface expression of E-selectin. A dual luciferase reporter assay indicated that high glucose and PUGNAc suppressed promoter activities of the cyclic AMP response element (CRE) and enhanced those of activator protein 1 (AP-1). Enhanced CRE promoter activities in HuH-7 cells treated with dibutyryl cAMP or co-transfected with a protein kinase A expression vector pFC-PKA that enhances the phosphorylation of CRE binding protein (CREB) were suppressed by PUGNAc. In contrast, PUGNAc further increased the enhanced AP-1 promoter activity in cells transfected with a mitogen-activated protein kinase kinase kinase expression vector pFC-MEKK that enhances c-Jun phosphorylation. Immuno-blotting using an anti-O-GlcNAc antibody revealed that high glucose and PUGNAc accelerated protein O-GlcNAcylation and that there were substantial differences in the O-GlcNAcylated proteins in the cytoplasmic and nuclear fractions. In addition, PUGNAc increased the nuclear import of O-GlcNAcylated CREB. These results suggest that protein O-GlcNAcylation modulates the promoter activities of E-selectin gene, suppression of CRE and enhancement of AP-1, and enhances E-selectin protein expression on hepatocytes.

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© 2007 The Pharmaceutical Society of Japan
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