Resveratrol protects BV2 mouse microglial cells against LPS-induced inflammatory injury by altering the miR-146a-5p/TRAF6/NF-κB axis

Objective: To investigate the role of miR-146a-5p in the effects of resveratrol (RSV) on inflammatory response in BV2 mouse microglial cells. Materials and methods: BV2 cells were pretreated by RSV and stimulated with lipopolysaccharide (LPS). Cell Viability was checked using a MTT assay. Real-Time PCR was performed to detect the levels of pro-inflammatory cytokines (tumor necrosisfactor-α－TNF-α, interleukin-1β－IL-1β and interleukin-6 － IL-6) and miR-146a-5p expression. Western blot was used to analyze the protein expression of TNF receptor associated factor 6 (TRAF6) and phospho-nuclear factor kappa B (pNF-κB). Gain-of-function and loss-of-function analysis of miR-146a-5p was performed using transfection of miR-146a-5p mimic and miR-146a-5p inhibitor, respectively. Results: Pretreatment with RSV significantly and dose dependently inhibited LPS-induced production of TNF-α, IL-1β and IL-6 in BV2 cells. MiR-146a-5p was significantly upregulated after LPS treatment, and further increased in RSV and LPS-co-treated cells. MiR-146a-5p overexpression via miR-146a-5p mimic transfection downregulated the mRNA level of TNF-α, IL-1β and IL-6, as well as abrogated the protein expression of TRAF6 and pNF-κB in BV2 cells exposed to LPS. More importantly, the reducion of TNF-α, IL-1β and IL-6 level by RSV were reversed by miR-146a-5p silence via miR-146a-5p inhibitor transfection. Furthermore, silencing miR-146a-5p attenuated the inhibitory effect of RSV on the TRAF6/NF-κB pathway which was activated after induction with LPS. Conclusions: RSV can suppress LPS-induced inflammatory injury via modulating the miR-146a-5p/TRAF6/NF-κB axis in BV2 mouse microglial cells.