Abstract: Objective To investigate the effect of miRNA-145 (miR-145) on immuno-inflammatory reaction of foam cells by targeting CD40. Methods Mouse macrophage cell line RAW 264.7 cells cultured in vitro were randomly divided into model group (non-transfected), miR-145 mimics group (transfected miR-145 mimics), miR-145 inhibitor group (transfected miR-145 inhibitor) and silencing CD40 sequence group (transfected siCD40). Then oxidized low density lipoprotein (ox-LDL) was used to stimulate for 24 h to establish immune inflammatory damage cell model. Quantitative realtime polymerase chain reaction (RT-qPCR) and Western blot assay were used to detect the levels of CD40 mRNA and protein of each group. ELISA was used to detect the levels of inflammatory factors interleukin (IL) - 1, IL-6 and tumor necrosis factor (TNF) - α in cell supernatant. Results Compared with model group, the levels of CD40 mRNA, CD40 protein and IL-1, IL-6, TNF-α were all significantly decreased in miR-145 mimics group (P < 0.01). After transfected with miR-145 inhibitor, the above indexes were all significantly increased than those of model group and miR-145 mimics group (P < 0.01). After transfected with CD40 siRNA, the levels of CD40 mRNA, CD40 protein and IL-1, IL-6, TNF-α were all obviously decreased compared with those of miR-145 inhibitor group (P < 0.01). Conclusion MiR-145 can regulate the immune inflammatory process of foam cells through the target gene CD40, inhibit the activation of CD40/CD40L signaling pathway and inhibit inflammatory response.

Key words: microRNAs, antigens, CD40, foam cells, transfection, interleukin-6, tumor necrosis factor-alpha, miR-145