Engineered E. coli for the targeted deposition of therapeutic payloads to sites of disease

New drug platforms are needed which enable the directed delivery of therapeutics to sites of disease to maximize efficacy and limit off-target effects. Here, we report the development of PROT3EcT, commensal Escherichia coli engineered for the direct secretion of proteins into their surroundings. PROT3EcT is composed of four modular components: an E. coli chassis, a modified bacterial protein secretion system, a regulatable transcriptional activator, and a secretable therapeutic payload. We demonstrate that PROT3EcT can secrete fully functional payloads, including single-domain antibodies nanobodies (Nb), into the extracellular space. Nb-secreting PROT3EcT stably colonizes and maintains a functional secretion system within the intestines of mice. A single prophylactic dose of PROT3EcT that secretes a tumor necrosis factor-alpha (TNFα) neutralizing Nb, but not PROT3EcT alone, is sufficient to ablate TNF levels and prevent the development of injury and inflammation in a chemically-induced model of inflammatory bowel disease. This work lays the foundation for the development of PROT3EcT as a therapeutic platform for the treatment of at least gastrointestinal-based diseases.