Anti-inflammatory mechanism of polysaccharide from Pleurotus placentodes by modulating proteins, gut microbiota, and metabolism

Based on the structural features of polysaccharide PPp-W from Pleurotus placentodes , its anti-inflammatory mechanism was investigated using LPS-induced RAW264.7 macrophages and mouse models. In vitro, PPp-W suppressed IL-6 and TNF- α secretion via regulation of the NF-κB and MAPK signaling pathways. In vivo, PPp-W reduced immune organ indices (thymus, spleen, liver), ameliorated tissue damage, decreased serum IL-6 and TNF- α secretion, and suppressed ACP, LDH, and GOT activities, ameliorated hepatic oxidative stress by increasing SOD and GSH-Px activities while reducing MDA content. Proteomics revealed that PPp-W modulated pathways involved in transport, catabolism, signal transduction, immunity, and metabolism, altering inflammation-related proteins including NOS2 and BDKRB2. PPp-W downregulated BDKRB2, which mediates inflammation via NF-κB and MAPK pathways. Gut microbiota analysis showed increased diversity and optimized composition, with higher relative abundance of Alistipes , Alloprevotella , and Bacteroides , and lower abundance of Desulfovibrio and Lactobacillus . Metabolomics indicated that PPp-W modulated steroid hormone biosynthesis and cortisol synthesis/secretion, altering levels of cortisol and 15( S )-HpETE. In conclusion, PPp-W exerts multi-targeted anti-inflammatory effects by regulating protein expression, remodeling gut microbiota, and modulating metabolic pathways, highlighting its potential as a promising anti-inflammatory polysaccharide.