Cervus nippon var. mantchuricus water extract treated with digestive enzymes (CE) modulates M1 macrophage polarization through TLR4/MAPK/NF-κB signaling pathways on murine macrophages

Abstract

The objective of this study was to investigate the effects of Cervus nippon var. mantchuricus water extract treated with digestive enzymes (CE) on the promotion of M1 macrophage polarization in murine macrophages. Macrophages polarize either to one phenotype after stimulation with LPS or IFN-γ or to an alternatively activated phenotype that is induced by IL-4 or IL-13. Cell viability of RAW264.7 cells was determined by WST-1 assay. NO production was measured by Griess assay. IL-6, IL-12, TNF-α, and iNOS mRNA levels were measured by RT-PCR. IL-6, IL-12, and IL-10 cytokine levels were determined by ELISA. TLR4/MAPK/NF-κB signaling in RAW264.7 cells was evaluated by western blotting. The level of NF-κB was determined by immunoblotting. CE induced the differentiation of M1 macrophages. CE promoted M1 macrophages to elevate NO production and cytokine levels. CE-stimulated M1 macrophages had enhanced IL-6, IL-12, and TNF-α. CE promoted M1 macrophages to activate TLR4/MAPK/NF-κB phosphorylation. M2 markers were downregulated, while M1 markers were upregulated in murine macrophages by CE. Consequently, CE has immunomodulatory activity and can be used to promote M1 macrophage polarization through the TLR4/MAPK/NF-κB signaling pathways.