Dual oxidase in the intestinal epithelium of zebrafish larvae has anti-bacterial properties

Reactive oxygen species (ROS) function in a range of physiological processes such as growth, metabolism and signaling, and also have a pathological role. Recent research highlighted the requirement for ROS generated by dual oxidase (DUOX) in host-defence responses in innate immunity and inflammatory disorders such as inflammatory bowel disease (IBD), but in vivo evidence to support this has, to date, been lacking. In order to investigate the involvement of Duox in gut immunity, we characterized the zebrafish ortholog of the human DUOX genes. Zebrafish duox is highly expressed in intestinal epithelial cells. Knockdown of Duox impaired larval capacity to control enteric Salmonella infection.

Research highlights
► We have cloned the zebrafish ortholog of the human DUOX1 and DUOX2 genes.
► Zebrafish Duox is expressed in epithelia in immediate contact with pathogens.
► Depletion of Duox impairs larval ability to clear enteric infection.
► This demonstrates that Duox functions in vertebrate gut innate immunity in vivo.