Structure-activity relationships of sulfated glycoproteins from Codium fragile on nitric oxide releasing capacity from RAW264.7 Cells.

The effects of sulfate and protein contents as well as molecular weights of the sulfated glycoproteins (NF2) from Codium fragile on the immunomodulation were systematically investigated. The obtained NF2 derivatives displayed various amounts of proteins (2.3-8.7 %) and sulfates (4.3-8.1 %) as well as different molecular weights (47.3-128.0 × 10(3) g/mol). NF2 was not able to stimulate RAW264.7 cells to release NO without its protein moiety, which was essential to activate NF-κB pathway through the degradation and phosphorylation of IκB-α and the subsequent translocation of p65/p50 complex in the cell nucleus. In addition, the proteins in NF2 were required to trigger MAPK pathway for the phosphorylation of ERK1/2, p38, and JNK1/2 as well as the nuclear translocation of c-JUN and c-FOS. However, the protein moiety itself could not activate RAW264.7 cells, thus the complex formation of the polysaccharide and protein moieties in NF2 was pivotal to stimulate macrophage cells.