MiRNA143 Downregulated the Expression of Cyclophilin A to Inhibit the Progression of Atherosclerosis

Abstract

To investigate the influence of microRNA (miR)-143 on atherosclerosis and its working mechanism via cyclophilin A. Human acute monocytic leukemia cells (human acute monocytic leukemia cells, human THP-1 monocytes) were treated with ox-LDL 80 mg/L for 48 h to establish a foam cell model. The modeling was evaluated by oil red O staining. The expressions levels of miRNA-143 and CyPA were detected by q-PCR. RNA extracted was confirmed by SiO2 nano magnetic bead. Dual-luciferase reporter gene assay was used to verify the targeted regulatory relationship between miRNA-143 and CyPA. Next, the cells were transfected with miR-143 mimics and treated with a CyPA inhibitor (cyclophilin A). The expression levels of CyPA and downstream matrix metalloproteinases-9 (MMP-9) in the downstream were detected by q-PCR and western blot, respectively. No or few lipid droplets were observed in the normal THP-1 cells. After treatment with ox-LDL for 48 h, a large amount of red-stained lipid was observed in the cytoplasm, indicating that the THP-1 derived foam cell models were successfully constructed. q-PCR results indicated that miRNA-143 was significantly downregulated in the THP-1-derived foam cell model, whereas CyPA was upregulated (P < 0.05); the dual luciferase reporter gene assay was performed for miRNA-143 and 3'-UTR of CyPA, and the fluorescence intensity of the 3'-UTR vector group was significantly lower than that of the empty vector group (P < 0.05). Fluorescence intensity detection of mutations at the target site showed that it had no effect was produced on the fluorescence intensity. This implied a negative regulatory effect conferred of miRNA-143 on CyPA; As compared to the model group, transfection with miRNA-143 mimics led to a significant downregulation of CyPA mRNA (P < 0.05), which was accompanied by significant downregulation of both MMP-9 mRNA and protein (P < 0.05). MMP-9 was also significantly downregulated upon the addition of the CyPA inhibitor cyclosporine A (P < 0.05).