microRNA-155 inhibits immuno-inflammatory reaction of foam cells by targeting MyD88

JING Xiang-yang; LIU Yun-ling; LU Li-ping; LIANG Xue; LIU En-zhao

doi:10.11958/20170719

Abstract：Objective To investigate the effects of microRNA-155 (miR-155) on immuno-inflammatory reaction of foam cells by targeting MyD88 and the possible mechanism. Methods RAW264.7 macrophages were cultured in vitro and transfected with miR-155 mimics, miR-155 inhibitor, MyD88 siRNA and their negative control respectively, then ox-LDL stimulation was given to build foam cell model. The expression of MyD88 in foam cells was detected by RT-qPCR and Western blot assay. Moreover, the expression levels of interleukin (IL)-10, TGF-β1 and MCP-1 in supernatant were determined by ELISA. Results After being transfected with miR-155 mimics, the mRNA level of MyD88 remained unchanged compared with that of control group (P>0.05). The protein level of MyD88 decreased significantly (P<0.05), and the expression levels of IL-10, TGF-β1 and MCP-1 in supernatant also decreased significantly (P<0.05). After being transfected with miR-155 inhibitor, the mRNA level of MyD88 remained unchanged compared with that of control group (P>0.05). The expression levels of MyD88 protein and inflammatory cytokines increased significantly (P<0.05). After being transfected with MyD88 siRNA, the expression levels of MyD88 mRNA and protein decreased significantly, and the expression levels of inflammatory cytokines also decreased significantly (P<0.05). Conclusion miR-155 can negatively regulate inflammation by targeting MyD88 through the inhibition of translation.