BACKGROUND: Protease-Activated Receptor 2 (PAR2), a G-protein-coupled receptor, has been proved to be enhanced in human coronary atherosclerosis lesions. We aimed to investigate whether PAR2 actively participates in the atherosclerosis process.

MATERIAL AND METHODS: PAR2 expression was assessed in blood samples by RT-qPCR from healthy controls and patients with atherosclerosis. Human vascular smooth muscle cells (VSMCs) were treated with oxidative low-density lipoprotein (ox-LDL). After PAR2 overexpression by transfection, cell proliferation was determined by CCK-8, and cell migration was evaluated by Transwell assay. The protein expressions associated with cell growth and migration were measured by Western blot. The distribution of α-SMA in VSMCs was evaluated by immunofluorescence.

RESULTS: Expression of PAR2 was higher in patients with atherosclerosis compared with normal controls. PAR2 mRNA and protein expression was increased in ox-LDL-treated VSMCs compared with control cells. Induced overexpression of PAR2 in VSMCs led to a reduction in α-SMA expression compared to controls. In addition, PAR2 overexpression caused increased migration compared to normal controls, and upregulated MMP9 and MMP14 expression. PAR-2 overexpression promoted cell proliferation compared to control cells, and increased expression levels of CDK2, and CyclinE1, but reduced levels of p27. We preliminary explored the potential mechanism of PAR2, and results showed that overexpression of PAR2 increased expression levels of VEGFA and Angiopoietin 2 compared to controls. Moreover, overexpression of PAR2 enhanced production of tissue factor and IL-8 compared to normal controls.

CONCLUSIONS: PAR2 promotes cell proliferation and disrupts the quiescent condition of VSMCs, which may be a potential therapeutic target for atherosclerosis.

Keywords: atherosclerosis, Cell Dedifferentiation, Receptor, PAR-2, Cyclin-Dependent Kinase 2, Lipoproteins, LDL, Matrix Metalloproteinase 9, Muscle, Smooth, Vascular, Myocytes, Smooth Muscle, RNA, Messenger, Receptors, G-Protein-Coupled, transcriptional activation