Immunomodulatory activity of Ganoderma lucidum immunomodulatory protein via PI3K/Akt and MAPK signaling pathways in macrophage RAW264.7 cells

Ganoderma lucidum, a traditional edible and medicinal fungus, holds an important status in health care systems in China and other Asian countries. Fungal immunomodulatory protein (FIP), one of the active ingredients isolated from G. lucidum, is a class of naturally occurring proteins and possesses potential biological functions. This study was conducted to explore the molecular mechanism of its immunomodulatory potency in immune responses of macrophages. In vitro assays of biological activity indicated that rFIP-glu significantly activated macrophage RAW264.7 cells, and possessed the ability of pro-and anti-inflammation the cells. RNA sequencing analysis showed that macrophage activation involved Toll-like receptors and mitogen-activated protein kinases pathways. Furthermore, qRT-PCR indicated that phosphoinositide 3 kinase inhibitor LY294002 blocked the mRNA levels of MCP-1, MEK1/2 inhibitor U0126 reduced the mRNA levels of TNF- and MCP-1, and JNK inhibitor SP600125 prevented the up-regulation of iNOS mRNA in the rFIP-glu-induced cells. FIP-glu mediated these inflammatory effects not through a general pathway, instead through a different pathway for different inflammatory mediator. These data indicate the possibility that rFIP-glu has an important immune-regulation function and thus has potential therapeutic uses.