Bioengineered ROS-tolerant probiotic reshapes gut microbiota-host axis to ameliorate type 2 diabetes in male mice

The pandemic-scale progression of type 2 diabetes mellitus (T2DM) necessitates innovative interventions targeting the pathogenic triad of insulin resistance, dysregulation of lipid metabolism, and gut microbiome dysbiosis. Here, we report a synthetically bioengineered probiotic consortium (REcN-F/Ca) developed through directed metabolic adaptations of Escherichia coli Nissle 1917 (EcN) under iterative hydrogen peroxide selection, subsequently functionalized with fructooligosaccharide-calcium carbonate composites. REcN-F/Ca exhibits enhanced reactive oxygen species tolerance through upregulated antioxidant enzymes and hydrogen sulfide-mediated redox balancing, alongside improved gastrointestinal survivability. In high-fat diet-induced obese male mice, REcN-F/Ca restores gut microbiota diversity, enriches butyrogenic taxa (Lachnospiraceae and Blautia), and rescues short-chain fatty acids depletion. Transcriptomic profiling reveals PPAR signaling activation, driving lipid metabolism and suppressing adipose inflammation. These effects translate to systemic metabolic improvements with attenuated weight gain (-25.4%), restored glucose homeostasis, and reduced insulin resistance (HOMA-IR: -73.2%) in the obesity and T2DM murine model. Our findings establish REcN-F/Ca as a synthetically engineered probiotic that simultaneously corrects intestinal ecological perturbations and reverses host metabolic dysfunction, proposing a paradigm for metabolic syndrome management.