Lacticaseibacillus rhamnosus-Derived Extracellular Vesicles Alleviate Colitis via PPAR Signaling and the Gut Microbiota-Metabolite Axis.

Intestinal barrier dysfunction is a hallmark of inflammatory bowel disease (IBD), yet effective therapies remain limited, and the mechanisms of probiotic-derived extracellular vesicles (EVs) are poorly understood. Using complementary cell, murine, and intestinal organoid models, we investigated the protective effects of Lacticaseibacillus rhamnosus ZFML003-derived EVs (ZFML003-EVs). In Caco-2 cells, ZFML003-EVs restored barrier integrity by upregulating tight junction proteins (ZO-1, Occludin, Claudin-1). In DSS-induced colitis mice, oral administration alleviated colonic pathology and suppressed pro-inflammatory cytokines (TNF-α, IL-1β, iNOS), while also restoring gut microbiota and metabolic profiles. Multi-omics analysis identified PPARγ signaling as a key mediator, with ZFML003-EVs upregulating PPARγ target genes (Adipoq, Scd1, Plin1). Notably, GW9662-mediated PPARγ blockade completely abolished these effects, confirming PPARγ dependence. Collectively, ZFML003-EVs activate PPARγ to exert anti-inflammatory and barrier-repair effects, reshape gut microbiota and metabolism, and provide a theoretical basis for IBD-targeted therapy.