BACKGROUND: Arecoline, the most abundant areca alkaloid, has been reported to stimulate reactive oxygen species (ROS) production in several cell types. Overproduction of ROS has been implicated in atherogenesis. Hemeoxygenase-1 (HO-1) has cytoprotective activities in vascular tissues. This study investigated the effect of arecoline on adhesion molecule expression and explored the role of HO-1 in this process. METHODS: Human umbilical vein endothelial cells (HUVECs) were treated with arecoline, then ROS levels and the expression of adhesion molecules and HO-1 were analyzed and potential signaling pathways investigated. RESULTS: After 2h of arecoline treatment, ROS production was stimulated and reached a maximum at 12h. Expression of the adhesion molecules ICAM and VCAM was also induced. Glutathione pretreatment completely blocked arecoline-stimulated ROS production and VCAM expression, but not ICAM expression. Arecoline also induced HO-1 expression and this effect was partly due by ROS stimulation. Inhibition of c-jun N-terminal kinase (JNK) by SP600125, p38 by SB 203580, or tyrosine kinase by genistein reduced arecoline-induced HO-1 expression. In contrast, inhibition of ERK (extracellular signal-related MAP kinase) by PD98059 had no effect. Transfection of HUVECs with the GFP/HO-1 gene, which resulted in a 5-fold increase in HO-1 activity, markedly, but not completely, inhibited the decrease in cell viability caused by arecoline. CONCLUSIONS: This study demonstrates that, in HUVECs, arecoline stimulates ROS production and ICAM and VCAM expression. HO-1 expression is also upregulated through the ROS, tyrosine kinase, and MAPK (JNK and p38) signaling pathways. Crown
BACKGROUND:Arecoline, the most abundant areca alkaloid, has been reported to stimulate reactive oxygen species (ROS) production in several cell types. Overproduction of ROS has been implicated in atherogenesis. Hemeoxygenase-1 (HO-1) has cytoprotective activities in vascular tissues. This study investigated the effect of arecoline on adhesion molecule expression and explored the role of HO-1 in this process. METHODS:Human umbilical vein endothelial cells (HUVECs) were treated with arecoline, then ROS levels and the expression of adhesion molecules and HO-1 were analyzed and potential signaling pathways investigated. RESULTS: After 2h of arecoline treatment, ROS production was stimulated and reached a maximum at 12h. Expression of the adhesion molecules ICAM and VCAM was also induced. Glutathione pretreatment completely blocked arecoline-stimulated ROS production and VCAM expression, but not ICAM expression. Arecoline also induced HO-1 expression and this effect was partly due by ROS stimulation. Inhibition of c-jun N-terminal kinase (JNK) by SP600125, p38 by SB 203580, or tyrosine kinase by genistein reduced arecoline-induced HO-1 expression. In contrast, inhibition of ERK (extracellular signal-related MAP kinase) by PD98059 had no effect. Transfection of HUVECs with the GFP/HO-1 gene, which resulted in a 5-fold increase in HO-1 activity, markedly, but not completely, inhibited the decrease in cell viability caused by arecoline. CONCLUSIONS: This study demonstrates that, in HUVECs, arecoline stimulates ROS production and ICAM and VCAM expression. HO-1 expression is also upregulated through the ROS, tyrosine kinase, and MAPK (JNK and p38) signaling pathways. Crown