Immunomodulatory Effects Exerted By Poria Cocos Polysaccharides Via TLR4/TRAF6/NF-κB Signaling In Vitro And In Vivo

Poria cocos polysaccharide（PCP）is a major active ingredient in P.cocos,and it possesses various pharmacological properties,including anti-oxidative,anti-apoptotic,and anti-cancer activities.This study investigated the immunomodulatory mechanism by which PCP acts on RAW 264.7 macrophages and LLC tumors in mice.The concentrations of nitric oxide,as well as Th1,Th2,and Th17 cytokines were examined via Griess reaction and by using a bead-based cytokine assessment kit.qRT-PCR and western blotting were used to investigate relevant signaling molecule expression.Levels of nitric oxide,IL-2,IL-6,IL-17A,TNF,and IFN-γwere increased by PCP,while levels of IL-4 and IL-10 were unaffected.The addition of TAK-242（a TLR4 inhibitor）or assessment in TLR4-deficient C57BL/10ScNJ mice markedly reduced this effect.In C57BL/10J(TLR4^+/+wild-type)mice,organ immune activity indices were all elevated,and oral PCP delivery resulted in a significant reduction in tumor volume over a 25-day period.Relative to controls,TLR4,MyD88,TRAF-6,p-NF-κB and p-c-JUN expression significantly increased,while TRAM expression did not change.There was no PCP-dependent activation of MyD88,TRAF-6,TRAM,p-NF-κB,or p-c-JUN in TLR4-deficient mice.These results suggest that PCP may mediate immunomodulatory activity via TLR4/TRAF6/NF-κB signaling both in vitro and in vivo.