Colonic Transcriptional Profiling in Resistance and Susceptibility to Trichuriasis: Phenotyping a Chronic Colitis and Lessons for latrogenic Helminthosis

Background: Helminth, therapy is advocated to restore and maintain control of inflammatory responses, particularly chronic colitis. However, helminths can induce chronic colitis in susceptible individuals. Susceptibility has an immunogenetic basis: defining this is essential if nematode therapy is to be successfully and safely targeted in inflammatory bowel disease (IBD). To validate a preclinical mouse model we phenotyped the response to Trichuris muris in mice. We determined colonic transcriptional activity in naive and infected mice and linked differential gene expression to mechanistic pathways. Methods: T. muris-infected resistant (BALB/c) and susceptible (AKR) mice were studied to a chronic colitic timepoint (day 35). Colonic genome-wide expression was performed by microarray. Significant transcriptional changes were analyzed by cluster and gene ontology filtering and KEGG pathway mapping. Results: Day 35 infected AKR displayed chronic diarrhea, weight loss, and transmural colonic inflammation; BALB/c remained asymptomatic, cleared the infection, and demonstrated normal histology. Compared to BALB/c mice, infected AKR upregulated gene expression clusters were overrepresented by immune response, chemotaxis, and apoptosis pathways. Cellular/tissue homeostasis and tight junction pathways dominated downregulated AKR expression clusters. Infected AKR T-helper cell development/polarization markers demonstrated predominant T(H)1/T(H)17 transcriptional activity. Colitic AKR data mirrored established murine models and human colitis. Conclusions: T. muris infection in the mouse shows striking phenotypic and transcriptional similarities to widely used models of IBD and human IBD. This preclinical mouse model presents a platform to examine biological commonalities among chronic colitides. However, these data urge caution in untargeted therapeutic helminth use until risk/benefit in susceptible individuals is more fully understood.