Nusaiba Baker - Oral delivery of DNA-enzyme nanoparticles ameliorates inflammation in a murine model of ulcerative colitis
From Katie Gentilello on November 20th, 2018
Ulcerative colitis (UC) is a chronic relapsing disease characterized by epithelial barrier damage and disruption of immune homeostasis in the colon. Incidence is increasing every year, affecting 1-2 of every thousand persons in developed countries. Current treatments aim to alleviate inflammation as well as heal the damaged mucosa. Current therapeutic strategies include 5-aminosalicylates, corticosteroids, Immunosuppressants, or biologics. However, these treatments result in numerous off-target effects, and immunosuppression can be fatal.
A major cause of inflammatory symptoms is the release of cytokines from immune cells. These cytokines, such as IL-4, IL-5, TNF-a, and IFN-g signal to the body to cause symptoms such as fever, fatigue, swelling, and cachexia. GATA3, a transcriptional activator, is involved in T lymphocyte differentiation and signaling, and regulates the expression of cytokines such as IL-4, IL-5, and IL-13. Accordingly, knock down of GATA3 and subsequent cytokine expression is a promising strategy for treatment of inflammatory disease. A range of antisense and RNAi technologies have been tested, and among these approaches, DNA enzymes (Dzs) have shown the greatest promise in animal models and Phase 1 clinical trials. Dzs are canonical DNA oligonucleotides that catalytically degrade a specific complementary RNA sequence. Despite the success of soluble Dzs as a therapeutic intervention, delivering highly charged oligonucleotides across the plasma membrane, and preventing nuclease degradation are major challenges. To address these problems, we have developed GATA3 DNAzyme nanoparticle conjugates delivered via an oral hydrogel method that elucidate the stability and delivery issues. Preliminary evidence shows that conjugating ~100 Dzs to a 14-nm gold particle forms a complex (DzNP) that improves airway function in mouse models of asthma. Importantly, DzNPs use one order of magnitude lower Dz dose compared to their soluble counterparts. By delivering the DzNPs via an alginate-based hydrogel, the therapeutic DNA-coated nanoparticles survive the acidic environment of the stomach and are degraded in the small intestine. Thus, we have established a novel method of gene regulation using a synthetic biomaterial. This research will provide a foundation for future development of nanoparticle-based therapeutic strategies for numerous diseases.