Subcellular proteomic approach for identifying the signaling effectors of protein kinase C-β2 under high glucose conditions in human umbilical vein endothelial cells

The high glucose-induced activation of protein kinase C-beta 2 (PKC-beta(2)) has an essential role in the pathophysiology of diabetes-associated vascular disease. In the present study, human umbilical vein endothelial cells (HUVECs) were cultured in high and normal glucose conditions prior to being infected with a recombinant adenovirus to induce the overexpression of PKC-beta(2). The activity of PKC-beta(2) was also decreased using a selective PKC-beta(2) inhibitor. A series of two-dimensional electrophoresis images detected similar to 800 spots in the nuclei, and similar to 600 spots in the cytosol. Following intra- and inter-group cross-matching, 38 significantly altered spots were identified as high glucose-induced and PKC-beta(2)-associated nuclear proteins. In addition to the observation that the regulation of key proteins involved in the nuclear factor (NF)-kappa B signaling cascade occurred in the cytosol, various transcription factors, including peroxisome proliferator-activated receptor delta (PPAR-delta), were also altered in the nuclei. A human protein-protein interaction network of potential connections of PKC-beta(2)-associated proteins was constructed in the proteomics investigation using Biological General Repository for Interaction Datasets. The results indicated that PKC-beta(2) may be involved in high glucose-induced glucose and lipid crosstalk by regulating PPAR-delta. In addition, NF-kappa B inhibitor-interacting Ras-like protein 1 may be important in the PKC-beta 2-NF-kappa B inhibitor-NF-kappa B signaling pathway in HUVECs under high-glucose conditions.