Julia Ganz Judith Eisen Laboratory

Institute of Neuroscience, University of Oregon

Neural regulation of intestinal inflammation in a Hirschsprung disease model

Julia Ganz

Summary

This work funded by this award aimed to understand if reduction in the number of enteric neurons in a zebrafish Hirschsprung disease model leads to a change in gut motility, causing changes in gut microbiota composition and resulting in increased gut inflammation. To investigate changes in gut motility, we established a high-resolution spatio-temporal analysis of gut motility using a novel analysis method that allows us to determine six different gut motility parameters (Ganz et al., 2016). We tested this novel analysis method and found that comparing gut motility patterns in fed with unfed wildtype zebrafish siblings revealed higher wave frequency and a trend to increased wave amplitude in fed larvae compared to unfed larvae. No other parameters were affected by providing food, suggesting that feeding affects very specific aspects of gut motility. In addition, we investigated changes in gut motility in a zebrafish ret mutants, a Hirschsprung disease model, and found that the amplitude of contractions shows a trend to be reduced in compared to wildtypes. We also analyzed the composition of the gut microbiota in zebrafish larvae with fewer enteric neurons. We find that the range of bacterial colonization shows a trend to be larger in mutants compared to wildtype siblings. In contrast, the diversity of the microbiota is larger in wildtypes than in their mutant siblings. Finally, we investigated if zebrafish larvae with fewer enteric neurons have increased inflammation in the distal gut by measuring number of neutrophils present. We find no significant increase in neutrophil influx between mutants with fewer enteric neurons and their wildtype siblings. In conclusion, we developed sophisticated software to analyze motility patterns in the zebrafish gut. We find that changes in the ENS lead to changes in microbiota composition and the range of microbial colonization, however these changes do not show a clear correlation with gut inflammation.