Vascular peroxidase 1 mediates hypoxia-induced pulmonary artery smooth muscle cell proliferation, apoptosis resistance and migration

• Published in: Cardiovascular research Vol. 114; no. 1; pp. 188 - 199
• Main Authors: You, Baiyang, Liu, Yanbo, Chen, Jia, Huang, Xiao, Peng, Huihui, Liu, Zhaoya, Tang, Yixin, Zhang, Kai, Xu, Qian, Li, Xiaohui, Cheng, Guangjie, Shi, Ruizheng, Zhang, Guogang
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.01.2018
• Subjects: NF-κB; Hypoxia; Vascular peroxidase 1; Pulmonary vascular remodelling; Pulmonary artery smooth muscle cells
• ISSN: 0008-6363; 1755-3245
• DOI: 10.1093/cvr/cvx234

Abstract Aims Reactive oxygen species (ROS) play essential roles in the pulmonary vascular remodelling associated with hypoxia-induced pulmonary hypertension (PH). Vascular peroxidase 1 (VPO1) is a newly identified haeme-containing peroxidase that accelerates oxidative stress development in the vasculature. This study aimed to determine the potential role of VPO1 in hypoxia-induced PH-related vascular remodelling. Methods and results The vascular morphology and VPO1 expression were assessed in the pulmonary arteries of Sprague-Dawley (SD) rats. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) and VPO1 expression and HOCl production were significantly increased in hypoxic rats, which also exhibited obvious vascular remodelling. Furthermore, a hypoxia-induced PH model was generated by exposing primary rat pulmonary artery smooth muscle cells (PASMCs) to hypoxic conditions (3% O2, 48 h), which significantly increased the expression of NOX4 and VPO1 and the production of HOCl. These hypoxic changes were accompanied by enhanced proliferation, apoptosis resistance, and migration. In PASMCs, hypoxia-induced changes, including effects on the expression of cell cycle regulators (cyclin B1 and cyclin D1), apoptosis-related proteins (bax, bcl-2, and cleaved caspase-3), migration promoters (matrix metalloproteinases 2 and 9), and NF-κB expression, as well as the production of HOCl, were all inhibited by silencing VPO1 with small interfering RNAs. Moreover, treatment with HOCl under hypoxic conditions upregulated NF-κB expression and enhanced proliferation, apoptosis resistance, and migration in PASMCs, whereas BAY 11-7082 (an inhibitor of NF-κB) significantly inhibited these effects. Conclusion Collectively, these results demonstrate that VPO1 promotes hypoxia-induced proliferation, apoptosis resistance, and migration in PASMCs via the NOX4/VPO1/HOCl/NF-κB signalling pathway.