RNAi-mediated silencing of TNF-α converting enzyme to down-regulate soluble TNF-α production for treatment of acute and chronic colitis.

Elevated level of tumor necrosis factor-α (TNF-α), one of the inflammatory cytokines, is considered to be a potential target for the inflammatory bowel disease (IBD) therapy. Recently, TNF-α converting enzyme (TACE), a sheddase playing an important role in cleaving and releasing bioactive soluble TNF-α, has been challenged with inhibitors to treat inflammatory diseases. Here, we report a novel anti-TNF-α strategy using a short hairpin RNA silencing TACE (shTACE) to prevent and treat colitis. The shTACE formed stable complexes with nona-arginine-based bio-cleavable disulfide bond-linked poly (arginine) (PAs-s) for enhanced gene delivery. Systemically administered shTACE/PAs-s peptoplexes efficiently decreased TNF-α levels, increased survival and alleviated pathophysiological parameters representing colitis severity. Our results demonstrate effectiveness and safety of shTACE/PAs-s peptoplexes with the capacity of overcoming acute and chronic ulcerative colitis through modulation of excessive inflammatory responses in the colon, providing a strong potential as a therapeutic agent for a broad variety of inflammatory diseases.