Zebrafish modeling of intestinal injury, bacterial exposures, and medications defines epithelial in vivo responses relevant to human inflammatory bowel disease

Genome-wide association studieshave identified over 200 genomic loci associated to inflammatory bowel disease (IBD)1. High effect risk alleles define key roles for genes involved in bacterial response and innate defense2. More high-throughput in vivo systems are required to rapidly evaluate therapeutic agents. We visualize, in zebrafish, the effects on epithelial barrier functionand intestinal autophagy of one-course and repetitive injury. Repetitive injury induces increased mortality, impaired recovery of intestinal barrier function, failure to contain bacteria within the intestine, and impaired autophagy. PGE2 administration protected against injury by enhancing epithelial barrier functionand limiting systemic infection. Effects of IBD therapeutic agents were defined; mesalamine showed protective features during injury while 6- mercaptopurinedisplayed marked induction of autophagy during recovery. Given the highly conserved nature of innate defense in zebrafish, it represents an ideal model system with which to test established and new IBD therapies targeted to the epithelial barrier.