Microrna-145 accelerates the inflammatory reaction through activation of NF-κB signaling in atherosclerosis cells and mice

Abstract

Atherosclerosis (AS) is a chronic inflammation, which is a major cause of morbidity and mortality in the world. Accumulative evidences have demonstrated that miRNAs exert crucial roles in the development of AS. However, the effects of miR-145 and its underlying molecular mechanism remain incompletely clear. The aim of the present study is to explore the function of miR-145 in the occurrence and development of AS through investigating its role in inflammatory reactions. High-fat diet (HFD)-treated ApoE−/− mice were used as an in vivo model of atherosclerosis (AS). OxLDL-induced macrophages was employed as cell models of atherosclerosis. RT-PCR was used to evaluate the transfected efficiency of miR-145 mimic and inhibitor. RT-PCR and ELISA were performed to detect the expression of miR-145, and inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), C-C motif chemokine ligand 2 (CCL-2), CCL-4 and CCL-7. Western blotting was used to evaluate the protein expression of nuclear factor κB (NF-κB) and its related proteins such as phosphorylated-signal transducer and activator of transcription 3 (p-STAT3), p-IκBα and acetylated p65 (ac-p65). Hematoxylin and eosin (H&E) staining were conducted to examine atherosclerotic lesion. Immunohistochemistry was carried out to detect the expression of α-smooth muscle Actin (α-SMA) and CD68. Luciferase reporter assay were carried out to examine the effect of miR-145 on the transcriptional activity of NF-κB. Our results showed that over-expression of miR-145 promoted the expression of IL-1β, TNF-α, CCL-2, CCL-4 and CCL-7 through promotion of NF-κB, p-IκBα, p-STAT3 and ac-p65 expression in vivo and in vitro. Besides, down-regulation of miR-145 expression relieved the aortic sinus lesion, increased the number of VSMCs and decreased the number of macrophages. In conclusion, our study demonstrated that miR-145 accelerated the inflammatory reaction through activation of NF-κB signaling in AS.