Mechanism of macrophage activation induced by β-glucan produced from Paenibacillus polymyxa JB115

β-Glucans are heterogeneous groups of glucose polymers found in the cell walls of fungi, plants and some bacteria. Our previous report showed that a novel β-1,3/1,6-glucan produced from Paenibacillus (P.) polymyxa JB115 can induce nitric oxide (NO) production in RAW264.7 cells. In the present study, the β-glucan significantly increased luciferase activity in cells transfected with NFκB or AP1, but not STAT1, reporter vector DNA, which contain their binding promoter site. All specific NFκB and MAPKs pathway inhibitors (pyrrolidine dithiocarbamate, AG490, U0126, SB203580 and SP600125) remarkably attenuated NO production induced by the β-glucan. Furthermore, Western blot analysis revealed that the stimulation of Raw264.7 cells by β-glucan induced phosphorylation of IκB and the consequent translocation of NFκB into the nucleus. Meanwhile, phosphorylation of ERK1/2, JNK/SAPK and p38 MAPKs in cytoplasm were also confirmed. All these results indicated that β-glucan from P. polymyxa JB115 activates macrophages through MAPKs and NFκB signaling pathway.