Activation of α7 nicotinic acetylcholine receptor protects against oxidant stress damage through reducing vascular peroxidase-1 in a JNK signaling-dependent manner in endothelial cells

Abstract

Aim: Alpha7 nicotinic acetylcholine receptor (α7nAChR), a subtype of nAChR regulating neurotransmission in central nervous system, is an essential regulator of cholinergic anti-inflammatory pathway in periphery. The present study was to determine the effects of activation of α7nAChR on oxidant stress-induced injury in endothelial cells. Methods: Cultured human umbilical vein endothelial cells were treated with H 2 O 2 (400 μM) or H 2 O 2 plus PNU-282987 (10 μM). Cell viability and membrane integrity were measured. Annexin V + PI assay, immunoblotting of bcl-2, bax and cleaved capase-3, and immunofluorescence of apoptosis inducing factor (AIF) were performed to evaluate apoptosis. Protein expression of vascular peroxidase-1 (VPO-1) and phosphor-JNK were measured by immunoblotting. Results: Activation of α7nAChR by a selective agonist PNU-282987 prevented H 2 O 2 -indced decrease of cell viability and increase of lactate dehydrogenase release. Activation of α7nAChR markedly reduced cell apoptosis and intracellular oxidative stress level. Moreover, activation of α7nAChR reduced H 2 O 2 -induced VPO-1 protein upregulation and JNK1/2 phosphorylation. The inhibitory effect of α7nAChR activation on VPO-1 was blocked by JNK inhibitor SP600125. In addition, pretreatment of α7nAChR antagonist methyllycaconitine blocked the cytoprotective effect of PNU-282987. Conclusion: These results provide the first evidence that activation of α7nAChR protects against oxidant stress-induced damage by suppressing VPO-1 in a JNK signaling pathway-dependent manner in endothelial cells. Copyright © 2014 S. Karger AG, Basel.