Fig. 6

PDCD4 was a downstream target of miR-21a-5p and further regulated inflammatory responses of macrophages through the NF-κB signaling pathway. A Venn diagram of the overlapping target genes presented in Pg.LPS (-) + Quercetin (-) and Pg.LPS ( +) + Quercetin (-) groups. B The target sites of miR-21a-5p in the PDCD4 sequence predicted by bioinformatic software. C The construction profile of the pLUC-PDCD4 vector, which contained the miR-21a-5p target sites in the PDCD4 3′-UTR. D, E The results of dual-luciferase reporter assay after the co-transfection of the miR-21a-5p mimic, inhibitor, and their NC with PDCD4-WT-3′-UTR or PDCD4- mutant-type (MUT)-3′-UTR. F–H Western blot and immunofluorescence staining of the target protein PDCD4 in RAW264.7 cells after the transfection of the miR-21a-5p mimic, inhibitor, and their NC. I–K Effect of quercetin on the expression of inflammatory genes and proteins (IL-1β, IL-6, iNOS and TNF-α) through qRT-PCR and western blot in macrophages transfected with siNC and siPDCD4. L, M Western blot and its quantitative analysis of p-P65 following transfection of macrophages with siNC and siPDCD4. (^*p < 0.05, ^**p < 0.01 and ^***p < 0.001; Data are represented as the mean ± SEM, n = 3)