Helixor-M Suppresses Immunostimulatory Activity through TLR4-Dependent NF-κB Pathway in RAW 264.7 Cells

Abstract

Inflammation causes a protective immune response, which can be observed by examining the inflammatory responses of macrophages. Macrophages release various immunostimulatory factors when destroying external pathogens. We induced lipopolysaccharides (LPS) in RAW 264.7 cells, a macrophage cell line, to determine whether Helixor-M can cause immuno-suppression. Helixor-M is known to have anticancer and immune effects. However, an indicator that regulates immunity has not been clearly confirmed. To this end, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was conducted to confirm Helixor-M was not cytotoxic. Western blotting and real-time polymerase chain reaction (RT-PCR) confirmed the anti-inflammatory effects. Additionally, immunofluorescence assay confirmed the translocation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65, a representative inflammatory pathway. Helixor-M was found to be non-cytotoxic, induce the NF-κB pathway, and reduce the levels of pro-inflammatory cytokine and mitogen-activated protein kinase (MAPK). We found Helixor-M affected the PI3K/AKT/JNK pathway. Therefore, we confirmed Helixor-M acts as an anti-inflammatory agent through NF-κB, TLR4 and PI3K inhibition and that it could be an effective immunosuppressive drug.