Fig. 4

MiR-146a-5p delivered by hucMSC-EVs targets TRAF6 and mediates the anti-inflammatory effect of hucMSC-EVs in vitro. A Potential miR-146a-5p binding site on the 3′-UTR of TRAF6. B The luciferase assay shows that the cotransfection of the TRAF6 3′-UTR and miR-146a-5p mimic reduced luciferase activity in HEK293 cells. C Relative levels of miR-146a-5p in extracellular vesicles derived from hucMSCs transfected with the miR-146a-5p mimic or inhibitor. D miR-146a-5p expression in RAW264.7 cells from each group was assessed by qRT–PCR. E The cell viability of different treatment groups was determined by the CCK-8 assay. F–I The levels of TNF-α, IL-1β, IL-6, and IL-10 in the cell supernatant isolated at 24 h after exposure to SM were visualized by ELISA. J The expression of TLR4/NF-κB signaling pathway-related proteins isolated from cells at 24 h after exposure to SM was visualized by western blotting. Full-length blots are presented in Additional file 1: Fig. S6. The data are presented as the mean ± SD of individuals included in each group (n = 3) and representative of at least three independent experiments. *P < 0.05; **P < 0.01; and ***P < 0.001