Sulfated polysaccharides of brown seaweeds are ligands of toll-like receptors

The interaction of sulfated polysaccharides (fucoidans) from brown seaweeds Laminaria japonica, Laminaria cichorioides, and Fucus evanescens with Toll-like receptors (TLRs) expressed on membranes of human embryonic kidney epithelial cells (HEK293-null, HEK293-TLR2/CD14, HEK293-hTLR4/CD14-MD2 and HEK293-hTLR2/6), has been investigated. In vitro fucoidans specifically interacted with TLR-2, TLR-4, and the heterodimer TLR-2/6; this resulted in activation of the transcription nuclear factor NF-κB. Composition the hydrolyzed fucoidan from F. evanescens was analyzed by gas-liquid chromatography and chromatography-mass spectrometry. Results indicated the absence of 3-hydroxytetradecanoic acid (3-OHC14), the basic fatty acid component of lipopolysaccharides in the analyzed preparation. Thus, the obtained results suggest that fucoidans from brown seaweeds possessing immunotropic activity are independent ligands for TLRs. They can induce genetically determined biochemical processes of protection organisms against pathogenic microorganisms.