Engineered outer membrane vesicle-like nanoparticles from Lactobacillus plantarum for oral IL-22 mRNA delivery and treatment of DSS-induced colitis

This study developed an engineered Lactobacillus plantarum-derived vesicle system for oral delivery of interleukin-22 mRNA (IL-22 mRNA) and evaluated its effects on epithelial barrier repair in DSS-induced colitis. The vesicle formulation, termed P-OMVs@IL-22 m, was prepared from L. plantarum protoplasts through lysozyme treatment, ultrasonic disruption, OptiPrep density-gradient purification, and incubation-based mRNA loading. The formulation achieved an IL-22 mRNA encapsulation efficiency of 72.43 ± 6.60% and a loading capacity of 35.97 ± 3.67 ng mRNA/µg P-OMV protein. mRNA loading increased the mean particle diameter from 119 ± 3 to 389 ± 7 nm and reduced the detectable particle concentration from 7.83 ± 0.81 × 10⁹ to 6.00 ± 0.78 × 10⁹ particles/mL. P-OMVs@IL-22 m protected IL-22 mRNA from RNase-mediated degradation, remained stable under simulated gastrointestinal conditions, and exhibited pH-associated release behavior. DiR-based IVIS imaging demonstrated persistent gastrointestinal signals after oral administration. In vitro, P-OMVs@IL-22 m was taken up by intestinal epithelial cells, increased IL-22 expression, activated STAT3 signaling, and enhanced Occludin, Claudin-1, and MUC2 expression. Functional assays showed increased transepithelial electrical resistance, reduced FITC-dextran permeability, and enhanced epithelial migration and proliferation. In DSS-induced colitis, oral P-OMVs@IL-22 m mitigated weight loss, lowered disease activity index scores, preserved colon length and tissue architecture, reduced inflammatory cytokine production, and restored epithelial barrier proteins. RNA sequencing and validation analyses linked treatment to changes in lipid metabolism, proteolysis, MAPK signaling, and mTOR-related pathways. These findings establish a preclinical proof-of-concept for engineered probiotic-derived vesicles as an oral IL-22 mRNA delivery platform for epithelial barrier repair in DSS-induced colitis.