Cyclooxygenase-2 Silencing for the Treatment of Colitis: A Combined In Vivo Strategy Based on RNA Interference and Engineered Escherichia Coli

Abstract

Nonpathogenic-invasive Escherichia coli (InvColi) bacteria are suitable for genetic transfer into mammalian cells and may act as a vehicle for RNA Interference (RNAi) in vivo. Cyclooxygenase-2 (COX-2) is overexpressed in ulcerative colitis (UC) and Crohn's disease (CD), two inflammatory conditions of the colon and small intestine grouped as inflammatory bowel disease (IBD). We engineered InvColi strains for anti-COX-2 RNAi (InvColi(shCOX2)), aiming to investigate the in vivo feasibility of a novel COX-2 silencing strategy in a murine model of colitis induced by dextran sulfate sodium (DSS). Enema administrations of InvColi(shCOX2) in DSS-treated mice led to COX-2 downregulation, colonic mucosa preservation, reduced colitis disease activity index (DAI) and increased mice survival. Moreover, DSS/InvColi(shCOX2)-treated mice showed lower levels of circulating pro-inflammatory cytokines and a reduced colitis-associated shift of gut microbiota. Considering its effectiveness and safety, we propose our InvColi(shCOX2) strategy as a promising tool for molecular therapy in intestinal inflammatory diseases.

Oral Delivery of Biologics for Precision Medicine

“…With the same purpose, L. lactis was also modified to secret IL‐10 and IL‐27 150,154. Other bacteria employed for this approach are genetically modified Bacteroides ovatus (B. ovatus) and non‐pathogenic invasive Escherichia coli (E. coli ), which contributed to treating IBD,146,151 colon cancer,152 or were used for vaccination153 in animal models successfully. In a clinical study, genetically modified L. lactis that secrets anti‐inflammatory cytokine IL‐10 has been packaged in enteric capsules for ulcerative colitis treatment; however, the study failed to pass Phase II in 2009 (NCT00729872).…”

Engineered Probiotics for Detection and Treatment of Inflammatory Intestinal Diseases

“…Cyclooxygenase-2 (COX-2) is an enzyme induced by proinflammatory cytokines including TNF-α and is overexpressed in the colonic mucosa of IBD patients (Singer et al, 1998). Using the two genes previously mentioned, non-pathogenic invasive E. coli was engineered to transfer anti COX-2 RNAi to silence the expression of this enzyme resulting in positive effects on DSS-induced colitis in mice (Spisni et al, 2015).…”

Gene therapy using bacterial vectors

“…On the other hand, we and others have repeatedly seen in experiments that control groups receiving mock vectors very often showed a difference to the groups receiving no treatment at all. It suggests that the vectors have an immunomodulatory effect (41)(42)(43). This is not a negative finding per se, but it complicates the design of experiments to prevent bias in interpretation (44).…”

“…The inflammatory process has several regulatory control points that can be blocked by small interfering RNA. In a recent study an Italian group showed that by inhibiting the production of cyclooxygenase-2 the colitis severity can be significantly reduced (41). Interfering RNA was produced by invasive Escherichia applied via enema.…”