Engineered probiotic Escherichia coli Nissle 1917 delivery of GPX4 suppresses pyroptosis and protects against sepsis

Sepsis remains a leading cause of mortality worldwide, driven by dysregulated inflammation and organ failure, with limited targeted therapies. Pyroptosis, mediated by gasdermin D (GSDMD), amplifies sepsis pathology through lipid peroxidation-dependent mechanisms, yet direct interventions are scarce. Leveraging the probiotic Escherichia coli Nissle 1917 (EcN) for gut-targeted delivery, we engineered EcN to secrete glutathione peroxidase 4 (GPX4), a pivotal antioxidant enzyme that curbs lipid peroxidation and pyroptosis. In an LPS-induced murine sepsis model, prophylactic oral EcN-GPX4 enhanced survival, mitigated multi-organ damage, and suppressed GSDMD cleavage across tissues. Dual mechanisms included: alleviation of oxidative stress and lipid peroxidation to block pyroptosis; and gut microbiota remodeling, enriching Ligilactobacillus murinus, which correlated with reduced LPS translocation and dampened arachidonic acid–linked pro-inflammatory metabolism. Via the gut–liver axis, EcN-GPX4 further attenuated hepatic TLR4/NF-κB signaling. This probiotic-based enzyme delivery offers a precise, microbiome-modulating strategy to interrupt pyroptotic amplification, with strong translational promise for sepsis management.