A. Apte1, J. Bardill2, B. Lyttle2, A. E. Vaughn2, T. R. Fauser1, S. Skopp1, J. Canchis1, S. Seal3, D. Jackson4, C. Zgheib1,4, K. W. Liechty1,4 1Laboratory For Fetal & Regenerative Biology, Department Of Surgery, University Of Arizona College Of Medicine And Banner Children’s At Diamond Children’s Medical Center, Tucson, AZ, USA 2Laboratory For Fetal & Regenerative Biology, Department Of Surgery, University Of Colorado School Of Medicine And Children’s Hospital Colorado, Aurora, CO, USA 3Advanced Materials Processing and Analysis Center, Nanoscience Technology Center, University Of Central Florida, Orlando, FL, USA 4Ceria Therapeutics Inc., Aurora, CO, USA
Introduction: Inflammatory bowel disease (IBD) represents a broad range of intestinal pathologies including Crohn’s disease and ulcerative colitis that result in poor growth, morbidity, and significant expense during childhood. Two key pathophysiologic processes common in IBD are dysregulated inflammation and oxidative stress. We have developed a novel therapeutic composed of a cerium oxide nanoparticle (CNP) conjugated to microRNA-146a (miR146a), which we have previously shown to have anti-inflammatory and free radical scavenging capabilities. We hypothesized that CNP-miR146a would improve colitis in a 2,4,6-Trinitrobenzenesulfonic acid (TNBS) murine model of acute colitis by decreasing inflammation.
Methods: To test our hypothesis, six-to eight-week old Balb/c male mice received an enema under anesthesia of 75 mg/kg of 2.5% TNBS diluted in 50% ethanol and 50% water to induce colitis. Control mice received an equivalent volume enema of 50% ethanol and 50% water. Following enema administration, mice were kept in single housing and weighed daily. Two days later, a subset of TNBS-injured mice were given a second enema under anesthesia containing 24 ng of CNP-miR146a in 200 ul of cellulose gel. Mice were returned to their housing and weighed daily. Five days following injury, the animals were euthanized and colon tissue was harvested. Colon lengths were measured using ImageJ software. Colon tissue was processed for RNA extraction and PCR was performed to evaluate relative gene expression of pro-inflammatory cytokines.
Results: Mice with colitis who were treated with CNP-miR146a enema demonstrated significant recovery in weight compared to untreated mice with colitis, at days 4 and 5 (p=0.03, p=0.02) (Figure 1E). Colon length in untreated mice with colitis was significantly shorter than uninjured controls (p=0.02) (Figure 1A) and colons from treated mice with colitis were significantly longer than colons from untreated mice with colitis (p=0.03) (Figure 1B). On molecular analysis of colon tissue, CNP-miR146a-treated mice had a significantly decreased relative gene expression of inflammatory markers IL-6 (p=0.03) (Figure 1C) and TNF-a (p<0.01) (Figure 1D) compared to untreated mice with colitis.
Conclusion: CNP-miR146a enema decreases proinflammatory gene expression, improves colon length and recovers weight loss resulting improved colitis in a TNBS mouse model. CNP-miR146a shows promising therapeutic potential for use in IBD while avoiding the side effects of systemic immunosuppression.
