Abstract 16665: Caveolin-1 and α7nachr Interaction is Essential in Preventing Nicotine Induced Vascular Inflammatory Response in Mice
Nicotine is an independent risk factor of and associated with the development of atherosclerosis. Dysfunction of endothelial Cavolin-1 (Cav-1) can accelerate atherosclerosis progression via boosting inflammation response. However, the causative link between nicotine and atherosclerosis remains unknown. Here, we utilized molecular and cellular experiments revealed that in human endothelial cells (HUVECs), 10-6 M nicotine increased intracellular oxygen free radical generation, inhibited eNOS activity, augmented pathological NO production from iNOS, promoted nitrative stress (Nitrotyrosine), and increased adhesion molecule expression when compared with vehicle. In vivo administration of nicotine upregulated plasma adhesion molecule levels and significantly increased nitrotyrosine levels in vascular tissue (2±0.4 fold compared with untreated group, p<0.05). Bioinformatics analysis predicted that α7nAChR motif (151YIDVRWFPF159 and 168FGSWSYGGW176) may interact with Cav-1 via Cav-1 scaffolding domain (82DGIWKASFTTFTVTKYWFYR101). The bioinformatic analysis was confirmed by immunocytochemistry and immunoprecipitation showing that α7nAChR co-localizes with caveolin-1 (Cav-1) and these two molecules interact reciprocally. Although 10-6M nicotine did not alter expression levels of Cav-1, it significantly decreased the interaction between Cav-1 and nicotine receptor (α7nAchR). After siRNA Cav-1 gene silence, nicotine treatment further significantly increased ROS generation (1.37 + 0.33 times vs. scrambled siRNA, p<0.05), enhanced pathological NO production (1.35 ± 0.4 fold, p<0.05), and increased adhesion molecule expression (1.4 ±0.4 fold, p<0.05). AMPKα1, a sensor of oxidative stress, was phosphorylated after nicotine treatment. However, siRNA AMPK gene silence failed to block nicotine induced adhesion molecule expression. Taken together, these results demonstrated that reduced α7nAchR/Cav-1interaction plays an important role in nicotine induced endothelial inflammatory response; this inflammation signal pathway is AMPK independent. Preserving and strengthening stability of Cav- 1/α7nAchR interaction is a potential target in treatment of vascular dysfunction caused by smoking.
Author Disclosures: R. Guo: None. Z. Yan: None. Q. Ma: None. Y. Zhang: None. X. Ma: None. Y. Wang: None.
- © 2015 by American Heart Association, Inc.