Tremella fuciformis Polysaccharides Inhibited Colonic Inflammation in Dextran Sulfate Sodium-Treated Mice via Foxp3+ T Cells, Gut Microbiota, and Bacterial Metabolites.

Tremella fuciformis is an edible medicinal mushroom, and its polysaccharide components are found to confer various health benefits. This study identified the protective effects of polysaccharides of Tremella fuciformis (TPs) against dextran sulfate sodium (DSS)-induced colitis in mice. High dose of TPs (HTPs) could prevent the colon from shortening, reduce activity of colonic myeloperoxidase and serum diamine oxidase (DAO), decrease the concentration of D-lactate, and alleviate the colonic tissue damage in colitic mice. HTPs treatment stimulated Foxp3+T cells, and promoted the production of anti-inflammatory cytokines whereas it reduced the production of pro-inflammatory and the portion of immunoglobulin A (IgA)-coated bacteria, which was related to modulation of immune responses. 16S rRNA sequencing analysis showed that TPs could significantly increase gut community diversity, and restore the relative abundances of Lactobacillus, Odoribacter, Helicobacter, Ruminococcaceae, and Marinifilaceae. According to metabolomic analysis, HTPs induced specific microbial metabolites akin to that in normal mice. Tyrosine biosynthesis, tryptophan metabolism, and bile acid metabolism were influenced in the HTPs group compared with those in the DSS group. HTPs could alleviate DSS-induced colitis by immunoregulation and restored the gut microbiota and microbial metabolites. The results indicated that HTPs have potential to be developed as a food supplement to ameliorate intestinal diseases.

Lectin from the Late Oyster Mushroom, Hohenbuehelia serotina (Agaricomycetes), and Its Novel Effect as an Adjuvant of the HBV DNA Vaccine.

The biological macromolecule Hohenbuehelia serotina lectin (HSL) was first isolated from dried fruiting bodies of the mushroom H. serotina and identified as a heterodimer with 2 subunits of the same molecular weight (15.6 kDa) but different isoelectric points. Lactose and d-galactose inhibited the hemagglutinating activity of HSL, whereas mental ions Mn2+ and Ca2+ could stimulate its hemagglutination. The HSL hemagglutinating activity was stable for 1 hour in NaOH and HCl solutions up to a concentration of 12.5 or 6 mmol/L. In addition, HSL was stable up to 50°C for 30 minutes; its hemagglutinating activity was halved at 60°C and totally inactivated above 90°C. HSL (10 µg) as an immune adjuvant co-inoculated with the proVAX/S2 vaccine enhanced the level of hepatitis B surface antigen in C57BL/6 mice, induced a high level of T-cell proliferation, and induced the expression of IFN- of CD4+ cells. We further illustrate that HSL, as an adjuvant upregulating the expression of major histocompatibility complex II, contributed to the maturation of dendritic cells. As the first lectin isolated from H. serotina, HSL is a potential adjuvant to chronic hepatitis B virus DNA vaccines and lays a foundation for the prevention of HBV infection.