In vitro and in vivo functional characterization of an immune activation Flammulina velutipes polysaccharide based on gut microbiota regulation

Flammulina velutipes contains bioactive polysaccharides that can activate the immune system. Here we report the functional characterization in an immunomodulatory F. velutipes polysaccharide (FVP) both in vitro and in vivo. In cell experiment, FVP was discovered to be an activator to induce the M1-polarization of the RAW 264.7 cells. In animal experiment, FVP was found to raise the gene expression of IL-1β, iNOS and ZO-1 in mice colon tissue. Moreover, it seemed to achieve the immune regulative function by raising the relative abundance of Allobaculum, Lactobacillus, Alloprevotella, Akkermansia and Bifidobacterium. Gut microbiota also caused the body’s functional changes, enriched the harmful chemicals’ degradation ability and weakened the metabolism of carbohydrates. These findings suggest that FVP is an immunomodulatory polysaccharide that can boost cellular immune responses and a potential prebiotic agent in regulating gut microbiota.