MicroRNA-381 regulates the occurrence and immune responses of coronary atherosclerosis via cyclooxygenase-2.

The present study aimed to measure the levels of microRNA-381 (miR-381) in the plaque tissues, peripheral blood mononuclear cells (PBMCs) and serum of patients with coronary atherosclerosis. In addition, the regulatory mechanisms of miR-381 and cyclooxygenase (COX)-2 in coronary atherosclerosis were investigated. A total of 36 patients with coronary atherosclerosis who received coronary endarterectomy at Linyi People's Hospital and Junan Hospital of Traditional Chinese Medicine (Linyi, China) between January 2013 and June 2016 were enrolled into the present study, while 39 healthy subjects were included as the control group. Peripheral blood was collected form all patients and healthy subjects. Plaque tissues were resected from patients with coronary atherosclerosis and adjacent artery intimal tissues were resected as the control tissues. Using quantitative polymerase chain reaction, the levels of miR-381 and COX-2 mRNA in the plaque tissues, PBMCs and serum were determined. In addition, COX-2 protein expression in the plaque tissues and PBMCs was measured by western blotting, while enzyme-linked immunosorbent assay was utilized to examine the protein content in the serum. To identify the direct interaction between miR-381 and COX-2 mRNA, dual-luciferase reporter assay was also conducted. The levels of COX-2 mRNA and protein in the plaque tissues, PBMCs and serum of patients with coronary atherosclerosis were significantly elevated compared with those in the corresponding control groups. However, the expression of miR-381 was significantly reduced in the coronary atherosclerosis patients. Dual-luciferase reporter assay revealed that miR-381 was able to directly target the 3'-untranslated region of COX-2 mRNA to regulate the expression of COX-2. Therefore, the present study demonstrated that enhanced levels of COX-2 expression in patients with coronary atherosclerosis are associated with the downregulation of miR-381 expression, while miR-381 may regulate the occurrence and immune responses of coronary atherosclerosis via COX-2.