To develop a genetically engineered probiotic, EcN-MT1, that secretes the anti-TNF-α nanobody MT1 for localized treatment of inflammatory bowel disease (IBD).
Approach:
Engineering and Screening: Escherichia coli Nissle 1917 (EcN) was engineered to secrete the anti-TNF-α nanobody MT1, with five signal peptides screened for optimal secretion.
Therapeutic Efficacy Evaluation: The therapeutic efficacy of EcN-MT1 was evaluated in a dextran sulfate sodium (DSS)-induced murine colitis model, assessing various health parameters and cytokine levels.
Key Findings:
The α-hemolysin (HlyA) signal peptide achieved the highest secretion of MT1 (4.6 mg/L).
EcN-MT1 demonstrated high binding affinity (EC50 27.9 nM) and effectively suppressed pro-inflammatory cytokines in macrophages.
Oral administration of EcN-MT1 significantly improved disease activity index (DAI) scores, reduced weight loss, and preserved colon length in the murine model.
Histopathological analysis showed reduced mucosal ulceration and immune cell infiltration, along with downregulated colonic Tnf and Il1b mRNA.
EcN-MT1 treatment restored gut microbial diversity and corrected dysbiosis.
Interpretation:
EcN-MT1 is a promising live biotherapeutic that provides localized TNF-α neutralization and promotes gut health in IBD.
Conclusion:
EcN-MT1 represents a novel strategy for IBD treatment, combining localized therapeutic effects with the benefits of engineered probiotics.
