Inhibition of inflammatory injure by polysaccharides from Bupleurum chinense through antagonizing P-selectin

• BCPs, the polysaccharides from Bupleurum chinense, impact P-selectin-mediated neutrophil adhesion.
• BCPs-treatment eliminated the interaction between P-selectin and its physiological ligand PSGL-1, which indicates BCPs are ligands of P-selectin with high affinity blocking the binding of P-selectin and PSGL-1.
• We provide a novel mechanism that polysaccharides inhibit the recruitment of leukocytes to inflammatory sites.

P-selectin-mediated adhesion between endothelium and neutrophils is a crucial process leading to acute inflammatory injure. Thus, P-selectin has been considered as promising target for therapeutics of acute inflammatory-related diseases. In the present study, the water-soluble polysaccharides (BCPs) were isolated from Bupleurum chinense, and we evaluated their therapeutical effects on acute inflammatory injure and antagonistic function against P-selectin-mediated neutrophil adhesion. Our results showed that BCPs significantly impaired the leukocyte infiltration and relieve lung injury in LPS-induced acute pneumonia model. BCPs significantly blocked the binding of P-selectin to neutrophils and inhibited P-selectin-mediated neutrophils rolling along CHO-P cell monolayer. The result from in vitro protein binding assay showed a direct evidence indicating that BCPs-treatment significantly eliminated the interaction between rhP-Fc and its physiological ligand PSGL-1 at protein level. Together, these results provide a novel therapeutical strategy for amelioration of inflammation-related disease processes by polysaccharides from B. chinense.