We isolated and purified a new polysaccharide (WFVP-N-b1) with a molecular weight of 20 kDa from Flammulina velutipes. Results showed that WFVP-N-b1 is composed of an α (1→6)-linked D-galactan backbone and branched at the O-2 of its Galp residues by an α-D-(1→6)-linked Manp attached to t-β-D-Glcp or t-α-D-Fucp side chains. WFVP-N-b1 can significantly induce cytokines secretion and release of toxic molecules. On a cellular level, WFVP-N-b1 is recognized by Toll-like receptor 4 (TLR4). Thereby, the hetero-galactan increased the phosphorylation of mitogen-activated protein kinases (MAPKs) and Akt, promoted degradation of IκB-α and the nuclear translocation of the NF-κB p65 subunit. Importantly, our results indicate that WFVP-N-b1 activated macrophage is mediated by autophagy, as blockade of WFVP-N-b1-induced autophagy by Baf-A1 significantly decreases macrophage activation. This is the first report that hetero-galactan-induced macrophage activation is mediated by autophagy. Collectively, WFVP-N-b1 activated RAW264.7 cells through MAPKs, autophagy, and Akt/NF-κB signaling pathways via TLR4 receptor.

macrophage, Flammulina velutipes, MAPKs, Akt/NF-κB, autophagy, hetero-galactan

• Compound ID: 21433
  

  /Variants 0/-34%a-D-Manp-(1-2)-+ | -6)-a-D-Galp-(1- /Variants 0/ is: 73%b-D-Glcp-(1-6)- OR (exclusively) 27%a-L-Fucp-(1-6)-

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  Structure type: structural motif or average structure
  
   
  
  Flammulina velutipes
  CSDB ID 48934 (all data & tools)