Efficient treatment of a preclinical inflammatory bowel disease model with engineered bacteria

We developed an engineered bacterium based, RNA interference mediated therapeutic method to significantly reduce the symptoms in the most frequently used animal model of inflammatory bowel disease. This transkingdom RNA interference strategy was based on the non-pathogenic E. coli MDS42 strain, which was engineered to constitutively produce invasin and histeriolysin cytolysin. These proteins enabled the bacteria first to invade the colon epithelium and then degrade in the phagosome. This allowed the delivery of a plasmid encoding shRNA targeting TNF alpha into the cytoplasm of the target cells. The expression levels of TNF alpha and other cytokines significantly decreased and the inflammatory symptoms were significantly reduced. With further safety modifications this method could serve as a safe and side-effect free alternative to biologicals targeting TNF-alpha.