Ganoderma Lucidum Polysaccharide Modulates Gut Microbiota and Immune Cell Function to Inhibit Inflammation and Tumorigenesis in Colon

This study investigated the effects of water-soluble polysaccharide extracted from the sporoderm-removed spores of Ganoderma lucidum (GLP) against AOM/DSS-induced inflammation, tumorigenesis, and gut microbiota modification, which has never been reported before. Our data revealed that GLP (200 and 300 mg/kg) decreased AOM/DSS-induced colitis and tumorigenesis, manifested by significantly reduced disease activity index score, and total number and size of tumors. Furthermore, GLP ameliorated AOM/DSS-induced microbiota dysbiosis, increased short-chain fatty acid production, and alleviated endotoxemia by inhibiting TLR4/MyD88/NF-κB signaling. Besides, GLP profoundly improved gut barrier function as evidenced by increased numbers of goblet cells, MUC2 secretion, and tight junction protein expressions. GLP treatment inhibited macrophage infiltration and downregulated IL-1β, iNOS, and COX-2 expressions. Additionally, GLP inhibited lipopolysaccharides (LPS)-induced inflammation markers and MAPK (JNK and ERK) activation in macrophage RAW264.7, intestinal HT-29, and NCM460 cells. In conclusion, these results indicate that GLP is a promising prebiotic for the treatment of colorectal cancer.