Achyranthes bidentata Polysaccharide Activates Nuclear Factor-Kappa B and Promotes Cytokine Production in J774A.1 Cells Through TLR4/MyD88 Signaling Pathway

Achyranthes bidentata Blume, a traditional Chinese medicine, is widely acknowledged for its function of invigorating the liver and kidneys and as a stranguria-relieving diuretic and used in the treatment of edema, gonorrhea, and other diseases. Polysaccharide (ABPS), isolated from Achyranthes bidentata Blume, has been demonstrated to have multiple biological activities including immunomodulatory effects. However, the mechanisms underlying the effects of ABPS have not been fully investigated. The present study is conducted to explore the underlying mechanism of immunomodulatory activities of ABPS. Results showed that ABPS significantly increased the secretion of IL-1β and TNF-α in J744 A.1 cells. Nitric oxide (NO) also significantly increased after ABPS treatment. The special antibodies (Toll-like receptor 4 (TLR4) antibody and CD14/TLR4 antibody) significantly decreased the activation, while the Toll-like receptor 2 (TLR2) antibody could not abolish this activation. Meanwhile, pyrrolidine dithiocarbamate (PDTC), a specific inhibitor of NF-κB, remarkably inhibited the secretion of IL-1β and TNF-α induced by ABPS in J744 A.1 cells. Western blotting (WB) and confocal laser scanning microscopy (CLSM) showed that ABPS promoted NF-κB translocation into the nucleus. Furthermore, the mRNA and protein expression of TLR4 and MyD88 were significantly increased after ABPS treatment. Taken together, these findings suggested that the immunomodulatory mechanism of ABPS was associated with the secretion of cytokines by stimulating the NF-κB pathway through TLR4/MyD88 signaling.