Acrolein Induces Cyclooxygenase-2 and Prostaglandin Production in Human Umbilical Vein Endothelial Cells. Roles of p38 MAP Kinase

Objective— Acrolein, a known toxin in tobacco smoke, might be involved in atherogenesis. This study examined the effect of acrolein on expression of cyclooxygenase-2(COX-2) and prostaglandin (PG) production in endothelial cells. Methods and Results— Cyclooxygenase (COX)-2 induction by acrolein and signal pathways were measured using Western blots, Northern blots, immunoflouresence, ELISA, gene silencing, and promoter assay. Colocalization of COX2 and acrolein-adduct was determined by immunohistochemistry. Here we report that the levels of COX-2 mRNA and protein are increased in human umbilical vein endothelial cells (HUVECs) after acrolein exposure. COX-2 was found to colocalize with acrolein-lysine adducts in human atherosclerotic lesions. Inhibition of p38 MAPK activity abolished the induction of COX-2 protein and PGE 2 accumulation by acrolein, while suppression of extracellular signal-regulated kinase (ERK) and JNK activity had no effect on the induction of COX-2 expression in experiments using inhibitors and siRNA. Furthermore, rottlerin, an inhibitor of protein kinase Cδ (PKCδ), abrogated the upregulation of COX-2 at both protein and mRNA levels. Conclusion— These results provide that acrolein may play a role in progression of atherosclerosis and new information on the signaling pathways involved in COX-2 upregulation in response to acrolein and provide evidence that PKCδ and p38 MAPK are required for transcriptional activation of COX-2.