Characterization of a polysaccharide from Rosa davurica and inhibitory activity against neutrophil migration

• RDPA1, a polysaccharide fraction from Rosa davurica, reduced the migration ability of neutrophils and impacted the migratory behavior.
• RDPA1 treatment impaired in vivo neutrophil infiltration in the peritonitis mice.
• We provide a novel mechanism that RDPA1 inhibits the recruitment of leukocytes to inflammatory sites, which suggests RDPA1 may be considered as a potential candidate for developing a novel anti-inflammatory agent.

The rapid recruitment of neutrophils from peripheral blood into infected sites is critical step for inflammatory responses; however, the excessive and improper recruitment can lead to serious tissue damages. Thus, it is a promising strategy to inhibit their excessive recruitment for treating inflammation-related disease. Here, we isolated a polysaccharide (RDPA1) from Rosa davurica, to evaluate its physicochemical property and inhibitory effects on neutrophil migration. RDPA1 was obtained by hot-water extraction, ethanol precipitation, and fractionated by DEAE-cellulose and Sepharose CL-6B columns. RDPA1 significantly inhibited in vitro migration of human neutrophils evaluated by transwell chamber and impacted the migratory behavior observed by time-lapsed microscopy, we found the migrated distance and average velocity of RDPA1-treated cells were greatly reduced. In addition, RDPA1 treatment impaired in vivo neutrophil infiltration in the peritonitis mice. RDPA1 exhibited significant blocking capacity of the interaction between β2 integrins and ICAM-1 evaluated by flow cytometry and in vitro protein binding assay. Together, these results suggest RDPA1 could be considered as a potential candidate for developing a novel anti-inflammatory agent.