Screening Of Immunological Activity Of Seven Fungal Polysaccharides And The Research On Immune Mechanism Of Pleurotus Eryngii Polysaccharide

Polysaccharide is one of the important bioactive components in edible fungi.Studies have shown that fungal polysaccharides could exert immune,anti-tumor,anti-oxidation,anti-virus and other biological activities.Therefore,the study of fungal polysaccharides has important significance and wide application prospects in the development of new drugs and health care products.Studies have shown that most of the bioactivity and function of polysaccharides are related to the immune system.Seven fungi polysaccharides were used in the present study.They are WHMP-A,WHMP-N from White Hypsizygus marmoreus,WACP-A,WACP-N from Agrocybe aegirita,WHEP-A,WHEP-N from Hericium erinaceus,WFVP-A,WFVP-N from Flammulina velutipes,WPOP-A,WPOP-N from Pleurotus ostreatus,WPEP-A,WPEP-N from Pleurotus eryngii,WAMP-A,WAMP-N from Amillariella mellea,respectively.Immune activity of these polysaccharides were screened in this study.Their effects on lymphocyte transformation,NK cell killing and macrophage phagocytosis were detected.Results showed that WHMP-A,WHMP-N,WHEP-A,WPOP-A,WPEP-A,WPEP-N,WAMP-A and WAMP-N significantly enhanced effect on lymphocyte transformation,NK cell killing and macrophage phagocytosis,indicating the polysaccharide exert significant activity of immune enhacement in vitro.We selected one of the polysaccharide,WPEP-N from Pleurotus eryngii,to further study its immunomodulatory action and its mechanism.In this study,WPEP-N-b was purified from WPEP-N.The immunomodulatory effects on macrophages and intestinal tract and its mechanism were studied.MTT,flow cytometry,Western-blot were used to detect the effect of WPEP-N-b on the activity of RAW264.7 macrophages.The results showed that WPEP-N-b could not only enhance the phagocytic capacity of RAW264.7 cells,but also promote the secretion of cytokines such as NO,IL-6,IL-1 and TNF-?.These results indicated that WPEP-N-b could activate RAW264.7 macrophages.On a cellular mechanistic level,WPEP-N-b could improve the expression of p-JNK,p-ERK and p-P38 proteins.Inhibiting the phosphorylation of JNK,ERK and P38 with specific inhibitors significantly inhibited the activation of macrophages.So we can draw a conclusion that WPEP-N-b activated macrophages through the MAPK pathway.The role of intestinal immunity in the immune system has attracted more and more attention.Caco-2 cells were applied to simulate the intestinal epithelium.The tight junction of intestinal epithelium was a barrier to protect the intestinal tract and affect the intestinal immune system.Therefore,we studied the effect of WPEP-N-b on tight junction of caco-2.The results showed that WPEP-N-b could increase the Trans Epithellal Electric Resistance of caco-2 cells,and increase the expression of Occludin,Claudin and ZO-1 mRNA and protein levels.Furhter results showed that WPEP-N-b could improve the expression of p-JNK,p-ERK,p-P38 and p-AKT proteins.All these results indicated that WPEP-N-b increased the tight junction of caco-2 cells through MAPK and AKT pathway.