Soluble receptor for advanced glycation end-products enhanced the production of IFN-γ through the NF-κB pathway in macrophages recruited by ischemia/reperfusion.

ABSTRACT

The current study investigated the role of sRAGE in the production of IFN­Î³ in macrophages with I/R treatment. The number of macrophages in myocardial tissues treated with I/R with or without sRAGE was determined via immunohistochemical staining. Proliferative activity of macrophages was analyzed by a 5­BrdU incorporation assay. Differentiation of macrophages was detected via immunofluorescence staining of iNOS (M1 macrophage marker). IFN­Î³ production, due to sRAGE stimulation, in Raw 264.7 macrophages and the NF­κB signaling pathway were measured using western blotting. A ChIP assay was used to examine the interactions between NF­κB and the promoter of IFN­Î³. The results showed that the number of macrophages in I/R­treated myocardial tissues was increased following sRAGE infusion. Proliferation of macrophages was increased significantly in the presence of sRAGE; after I/R treatment, the cells preferred to differentiate into M1 macrophages. IFN­Î³ expression in Raw 264.7 macrophages was suppressed by an NF­κB inhibitor (Bay117082) but enhanced by sRAGE, with or without I/R treatment. Furthermore, sRAGE increased the phosphorylation of IκB, IKK and NF­κB, as well as the translocation of NF­κB into the nucleus of Raw 264.7 macrophages, with or without I/R treatment. ChIP results showed that sRAGE promoted NF­κB binding to the promoter of IFN­Î³ in Raw 264.7 macrophages. Therefore, the findings of the present study indicated that sRAGE protected the heart from I/R injuries, which might be mediated by promoting infiltration and the differentiation of macrophages into M1, which would then synthesize and secrete IFN­Î³ through activating the NF­κB signaling pathway.