Polysaccharide from the edible insect Protaetia brevitarsis seulensis enhances interferon signaling in macrophages to inhibit norovirus infection 9014

Abstract Description Edible insects are increasingly recognized as promising nutraceutical sources with immune-modulating effects. This study focuses on the purification and structural analysis of polysaccharides from the larvae of Protaetia brevitarsis seulensis (PBSL), exhibiting antiviral properties against murine norovirus. Four polysaccharide fractions isolated from PBSL water extracts showed diverse molecular weights (458.5–627.3 kDa) and monosaccharide compositions, comprising glucose (42.4–99.2%), galactose (5.9–13.9%), rhamnose (0.7–18.7%), arabinose (3.8–5.4%), and glucuronic acid (0–15.3%). The immunomodulatory activity, indicated by interferon-β (IFN-β) production, was positively associated with higher levels of galactose, mannose, rhamnose, and uronic acid. Among these, the fraction PBS-P, eluted with 0.5 M NaCl, exhibited the strongest antiviral activity in vitro, with IFN-β production over 8 times higher than other fractions and 82 times higher than the PBSL water extract, establishing it as the primary antiviral component. PBS-P inhibited norovirus replication by inducing IFN-α, IFN-β, and TNF-α, and subsequently activating interferon-stimulated genes. Further examination revealed activation of the NF-κB, STAT1/2, and TBK1-IRF3 pathways by PBS-P. Oral administration of PBS-P reduced viral loads in the intestines of infected mice. This study identified the structural features of a polysaccharide from an edible insect and its antiviral mechanism. Funding Sources This research was supported by the National Research Foundation (NRF), funded by the Korean government (MSIT), 2023R1A2C1006827 and RS-2023-00222997. Topic Categories Innate Immune Responses and Host Defense: Molecular Mechanisms (INM)