Polysaccharides Attenuate Oxidative Stress and Inflammation in Macrophages through miR-155.

AIM

To investigate the function of polysaccharides (TFPS) in LPS-induced inflammation and oxidative stress of macrophages.

METHODS

RAW264.7 cells were pretreated with TFPS and then stimulated with 0.1 g/ml LPS. NFB, Akt, p38MAPK, MCP-1, and SOD-1 were analyzed by Western blotting. Cell viability was measured using MTT assays. Reactive oxygen species (ROS) production, real-time PCR, ELISA, and immunofluorescence staining were performed on RAW264.7 cells that were treated with LPS and/or TFPS to investigate the anti-inflammatory effect of TFPS.

RESULTS

LPS induced inflammation and ROS production and promoted the secretion of cytokines such as TNF- and IL-6. LPS also enhanced the nuclear translocation of NFB, which promoted inflammation by oxidative stress. However, pretreatment with TFPS profoundly inhibited the activation of Akt, p38MAPK, and NFB and attenuated the expression of MCP-1 in macrophages. Meanwhile, TFPS also decreased cytokine and ROS levels and attenuated cell inflammation after treatment with LPS. Moreover, miR-155, one of the key small RNAs which regulate NFB and inflammation in macrophages, was significantly downregulated.

CONCLUSION

TFPS inhibits LPS-induced oxidative stress and inflammation by inhibiting miR-155 expression and NFB activation in macrophages, which suggests that TFPS may be a potential reagent for inhibiting the development of inflammation.