Blockade by nifedipine of advanced glycation end product-induced CD40-CD40 ligand interaction in endothelial cells.

Advanced glycation end products (AGEs), the senescent macroprotein derivatives that form in increased amounts in diabetes, have been implicated in the pathogenesis of accelerated atherosclerosis. There is a growing body of evidence that CD40-CD40 ligand (CD40L) interaction also plays an important role in atherogenesis. However, the effects of AGEs on CD40-CD40L signaling in endothelial cells (ECs) remain to be elucidated. In this study, we investigated (i) whether injection of AGE-proteins to normal rats stimulates CD40L expression on circulating platelets and (ii) whether AGEs up-regulate CD40 mRNA levels in cultured ECs. We further examined the effects of nifedipine, one of the most popular dihydropyridine-based calcium antagonists, on CD40 gene expression in AGE-exposed ECs. Platelet surface CD40L expression was increased in AGE-bovine serum albumin (AGE-BSA)-injected rats, compared with nonglycated BSA administration. AGEs were found to induce up-regulation of CD40 mRNA levels in ECs, which were significantly blocked by nifedipine. These results suggest that AGEs could enhance CD40-CD40L interaction, thereby promoting atherosclerosis in diabetes. Blockade of CD40-CD40L signaling in ECs may be a molecular target for the vasculoprotective property of nifedipine.