Polysaccharide from Ganoderma atrum induces tumor necrosis factor-α secretion via phosphoinositide 3-kinase/Akt, mitogen-activated protein kinase and nuclear factor-κB signaling pathways in RAW264.7 cells

► We elucidated the mechanism of PSG-1-mediated immunomodulatory activities. ► PI3K/Akt/MAPK/NF-κB signaling pathway was activated by PSG-1 in RAW264.7 cells. ► PI3K/Akt/MAPK/NF-κB signaling pathway was involved in PSG-1-induced TNF-α secretion. ► Our results show that PSG-1 has the potential as a novel immunomodulating agent.