Immunomodulatory effects of the polysaccharide from Craterellus cornucopioides via activating the TLR4-NFκB signaling pathway in peritoneal macrophages of BALB/c mice.

Abstract The immunoregulatory effect and immunologic response mechanism of Craterellus cornucopioides (L.) Pers. polysaccharide (CCP) with a triple-helix structure on peritoneal macrophages was investigated in vitro for the first time. These studies demonstrated that treatment of peritoneal macrophages with 80 μg/mL CCP for 48 h significantly strengthened their phagocytic function as well as increases the activities of lysozyme (LZM), acid phosphatase (ACP) and succinodehydrogenase (SDH) when compared with the untreated group. Furthermore, Western Blot and quantitative real-time polymerase chain reaction (qRT-PCR) assays demonstrated that 80 μg/mL CCP activated macrophages, significantly increased mRNA expression of cytokines (IL-8, IL-1β, IFN-α and TNF-α) and upregulated the protein expression of cell membrane receptor TLR4, as well as its downstream protein kinase products (MyD88, TAK1, P-IKKα/β and P-MEK) through activation of the TLR4-NFκB pathway in peritoneal macrophages. In conclusion, these results showed that the immunomodulatory mechanism of CCP in peritoneal macrophages was associated with the release of NO, related enzymes and cytokines by stimulating the NF-κB p50 pathway via TLR4-MyD88-TAK1 signaling.