Interactions between Sulfated Polysaccharides from Sea Brown Algae and Toll-Like Receptors on HEK293 Eukaryotic Cells In Vitro

We studied the interactions between sulfated polysaccharides, fucoidans from sea brown algae Laminaria japonica , Laminaria cichorioides , and Fucus evanescens , with human Tolllike receptors (TLR) expressed on membranes of cultured human embryonic kidney cells (HEK293-null, HEK293-TLR2/CD14, HEK293-hTLR4/CD14-MD2, and HEK293-hTLR5). Fucoidans interacted with TLR-2 and TLR-4, but not with TLR-5, and were nontoxic for the cell cultures. L. japonica fucoidan (1 mg/ml), L. cichorioides fucoidan (100 μg/ml and 1 mg/ml), and F. evanescens fucoidan (10 μg/ml-1 mg/ml) activated transcription nuclear factor NF-κB by binding specifi cally to TLR-2. L. japonica fucoidan (100 μg/ml and 1 mg/ml), L. cichorioides fucoidan (10 μg/ml-1 mg/ml), and F. evanescens fucoidan (1 μg/ml-1 mg/ml) activated NF-κB via binding to TLR-4. These results indicated that fucoidans could induce in vivo defense from pathogenic microorganisms of various classes.