Isolation and Immunomodulatory Evaluation of Glycyrrhiza Polysaccharide-Induced Probiotics from Murine Gut Microbiota
Description
While low-molecular-weight Glycyrrhiza polysaccharide (LGP) demonstrates immunomodulatory effects through gut microbiota modulation, the specific LGP-responsive bacterial taxa and their therapeutic potential as next-generation probiotics (NGPs) remain poorly characterized. In this study, we isolated dominant LGP-induced bacterial strains (Bacteroides vulgatus and Parabacteroides sp.) from murine intestinal contents and systematically evaluated their probiotic potential using comprehensive NGPs selection criteria: 1) it has excellent gastrointestinal tolerance, and the survival rate in gastric juice with pH 2.5 and 0.5% cholate is over 90%; 2) broad-spectrum antibiotic susceptibility; 3) potent pathogen inhibition (Escherichia coli, Enterobacter cloacae, and Proteus vulgaris), and 4) absence of cytotoxicity or phagocytic interference in RAW264.7 macrophages (confirmed for heat-killed cells, supernatants, and lysates). In vivo experiments, we found that NGPs exhibited significant immunomodulatory abilities, B. vulgatus fresh culture (BX) stimulated 2.49-fold leukocyte proliferation, and parabacteroides sp. lysate (PL) elevated IL-10 production (1.33-fold). NGPs slao ameliorated hepatic injury markers, restored intestinal barrier integrity, enriched beneficial taxa (Akkermansia, Rikenella, UCG-010), enhanced SCFA production (isobutyrate, isovalerate, butyrate, valerate), and modulated critical metabolic pathways (LPS biosynthesis, TCA cycle, gluconeogenesis). These findings not only elucidate the microbial mechanisms underlying LGP's immunomodulation but also provide two well-characterized, gut-derived NGP candidates with validated multi-functional efficacy, meeting stringent safety and functionality requirements for therapeutic development.