Gut Commensal <i>Phocaeicola vulgatus</i> AF107-22 Alleviates Obesity-Induced Metabolic Syndrome via Promoting Gut Microbiota-Derived Spermidine Synthesis

Obesity-induced metabolic syndrome (MetS) is a prevalent metabolic disorder, and therapeutic strategies targeting the gut microbiota hold considerable promise. <i>Phocaeicola vulgatus</i> (<i>P. vulgatus</i>) is a gut commensal bacterium that plays an important role in modulating the composition and metabolism of gut microbiota. This study demonstrated that the abundance of <i>P. vulgatus</i> is significantly negatively correlated to obesity-induced MetS and complications in human metagenomic data. Oral gavage of <i>P. vulgatus</i> significantly ameliorated high-fat-diet (HFD)-induced MetS symptoms in mice, reducing body weight, systemic inflammation, and hepatic steatosis. Furthermore, multiomics analyses indicated that <i>P. vulgatus</i> treatment significantly enhanced the production of gut microbiota-derived spermidine and spermine. Subsequently, population-based analysis confirmed a strong negative correlation between plasma spermidine levels and MetS progression, supporting that such parameters may serve as potential biomarkers for MetS. This study reveals a potential mechanism, bridging commensal probiotic and spermidine metabolism, with implications for treating obesity-induced MetS.