Protein kinase C beta II upregulates intercellular adhesion molecule-1 via mitochondrial activation in cultured endothelial cells

Activation of protein kinase C (PKC) is closely linked with endothelial dysfunction. However, the effect of $PKC{\beta}II$ on endothelial dysfunction has not been characterized in cultured endothelial cells. Here, using adenoviral $PKC{\beta}II$ gene transfer and pharmacological inhibitors, the role of $PKC{\beta}II$ on endothelial dysfucntion was investigated in cultured endothelial cells. Phorbol 12-myristate 13-acetate (PMA) increased reactive oxygen species (ROS), p66shc phosphorylation, intracellular adhesion molecule-1, and monocyte adhesion, which were inhibited by $PKC{\beta}i$ (10 nM), a selective inhibitor of $PKC{\beta}II$. PMA increased the phosphorylation of CREB and manganese superoxide dismutase (MnSOD), which were also inhibited by $PKC{\beta}i$. Gene silencing of CREB inhibited PMA-induced MnSOD expression, suggesting that CREB plays a key role in MnSOD expression. Gene silencing of $PKC{\beta}II$ inhibited PMA-induced mitochondrial ROS, MnSOD, and ICAM-1 expression. In contrast, overexpression of $PKC{\beta}II$ using adenoviral $PKC{\beta}II$ increased mitochondrial ROS, MnSOD, ICAM-1, and p66shc phosphorylation in cultured endothelial cells. Finally, $PKC{\beta}II$-induced ICAM-1 expression was inhibited by Mito-TEMPO, a mitochondrial ROS scavenger, suggesting the involvement of mitochondrial ROS in PKC-induced vascular inflammation. Taken together, the results suggest that $PKC{\beta}II$ plays an important role in PMA-induced endothelial dysfunction, and that the inhibition of $PKC{\beta}II$-dependent p66shc signaling acts as a therapeutic target for vascular inflammatory diseases.