Flammulina velutipes polysaccharide exerts immunomodulatory function involving RSAD2 to regulate the NF-κB/MAPK signaling pathway in RAW264.7 macrophage cells and in mouse spleen cells.

There are ongoing efforts to explore the potential of natural bioactive substances including polysaccharides in immunological regulation and understand the mechanisms under their immune-regulating function. In this study, a polysaccharide from Flammulina velutipes (FVP-1) exhibited immunomodulatory in RAW264.7 macrophage cells and mouse spleen cells. FVP-1 increased the secretion of cytokines (like TNF-α, IL-6 and IL-1β) and their mRNA expression, upregulated the transcription and translation expression of COX-2 and iNOS, and enhanced the release of reactive oxygen species the phagocytic activity in macrophages, thereby promoting the maturation and transformation of certain lymphocytes. All these functions of FVP-1 depended to some extent on its concentration. The RSAD2 effector was involved in the immunomodulatory function of FVP-1 towards macrophages and mouse splenocytes, through mediating FVP-1's activation and regulation of the NF-κB/MAPK signaling pathway. These findings indicate the potential of FVP-1 as a natural immunomodulator and approach for improving immune function.