Immunological effect of fucosylated chondroitin sulfate and its oligomers from Holothuria fuscogilva on RAW 264.7 cells

Fucosylated chondroitin sulfate was obtained from the sea cucumber Holothuria fuscogilva (FCShf). The structure was elucidated by NMR and HILIC-FTMS analysis. FCShf contained a chondroitin core chain [→3)-β-D-GalNAc-(1 → 4)-β-D-GlcA-(1→]_n, where the sulfation positions were the O-4 or O-6 of the GalNAc residues. The ratio of sulfated and non-sulfated GalNAc at O-6 was 1:2, while the ratio of GalNAc at O-4 was 1:1. 2,4-disulfated-fucose (Fuc2,4S), 4-sulfated-fucose (Fuc4S) and 3,4-disulfated-fucose (Fuc3,4S) were attached to the O-3 of GlcA with a molar ratio of 1.00: 0.62: 1.32. The FCShf could significantly promote the proliferative rate, NO production and neutral red uptake of RAW 264.7 cells within the concentration range of 10–300 μg/mL. Compared with the fucosylation and deacetylation degrees, the molecular weight of FCShf had markedly influence on the activation of RAW 264.7 cells. A decrease in molecular weight dramatically improved the immunoregulatory activities. Furthermore, FCShf activated RAW 264.7 cells through TLR-2/4-NF-κB pathway.