A Polysaccharide from the Culinary-Medicinal Mushroom Pholiota nameko (Agaricomycetes) Inhibits the NF-κB Pathway in Dendritic Cells Through the TLR2 Receptor.

A polysaccharide purified from Pholiota nameko (PNPS-1) was found to have anticancer and anti-inflammatory activity. This study investigated the effect of PNPS-1 on the nuclear factor (NF)-κB signaling pathway of TLR2 small interfering RNA-silenced murine bone marrow-derived dendritic cells (BMDCs) and relevant mechanisms. The expression of messenger RNA of 4 NF-κB-related genes, including MyD88, IKBKB, RelA(p65), and CCL2, was determined by real-time polymerase chain reaction; the expression of the phenotype molecule intercellular adhesion molecule-1 (ICAM-1) by flow cytometry; the protein expression of IKKß and p65 by Western blot; the production of p65 by enzyme-linked immunosorbent assay; and the expression of p65 by immunocytochemistry. The results showed that TLR2-specific small interfering RNA could effectively inhibit the decrease in the expression of MyD88, IKBKB, CCL2, p65, and ICAM-1 in BMDCs induced by PNPS-1, and thus the transcription inactivation of NF-κB, which obviously suggests that PNPS-1 could downregulate the NF-κB signaling pathway via the TLR2 receptor.