An Alkali-extracted polysaccharide from Poria cocos activates RAW264.7 macrophages via NF-KB signaling pathway

An alkali-extracted polysaccharide (PCAPS1) was isolated and purified from the Poria cocos. Our results proved that PCAPS1 was a neutral polysaccharide with a molecular weight of 11.5 kDa. The monosaccharide composition, methylation and NMR analysis results displayed that the polysaccharide was mostly comprised of b-1,3-glucan with 1,4 and 1,6 branches. The Immune activity and mechanism of PCAPS1 were evaluated in RAW264.7 cells. The enzyme-linked immunosorbent assay (ELISA) analysis revealed that PCAPS1 increased the tumor necrosis factor-a (TNF-a) secretion. RNA-sequencing data analysis suggested that PCAPS1 activated macrophages by the classic NF-KB pathway. Real-time quantitative polymerase chain reaction (RT-qPCR) analysis confirmed that PCAPS1 enhanced mRNA expression levels of TNF-a and nuclear factor KB (NF-KB) in RAW264.7 cells. Simultaneously, the fluorescence nuclear transport experiment showed that PCAPS1 activated RAW264.7 cells by inducing the NF-KB p65 transloca-tion. Our results indicated that PCAPS1-induced TNF-a expression was mediated via the NF-KB signaling pathway. (c) 2023 The Authors. Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).