RT Journal Article SR Electronic T1 Chitin protects the gut epithelial barrier in a protochordate model of DSS-induced colitis JF Biology Open JO Biology Open FD Company of Biologists SP bio029355 DO 10.1242/bio.029355 VO 7 IS 1 A1 Liberti, Assunta A1 Zucchetti, Ivana A1 Melillo, Daniela A1 Skapura, Diana A1 Shibata, Yoshimi A1 De Santis, Rosaria A1 Pinto, Maria Rosaria A1 Litman, Gary W. A1 Dishaw, Larry J. YR 2018 UL http://bio.biologists.org/content/7/1/bio029355.abstract AB The gastrointestinal tract of Ciona intestinalis, a solitary tunicate that siphon-filters water, shares similarities with its mammalian counterpart. The Ciona gut exhibits other features that are unique to protochordates, including certain immune molecules, and other characteristics, e.g. chitin-rich mucus, which appears to be more widespread than considered previously. Exposure of Ciona to dextran sulphate sodium (DSS) induces a colitis-like phenotype similar to that seen in other systems, and is characterized by alteration of epithelial morphology and infiltration of blood cells into lamina propria-like regions. DSS treatment also influences the production and localization of a secreted immune molecule shown previously to co-localize to chitin-rich mucus in the gut. Resistance to DSS is enhanced by exposure to exogenous chitin microparticles, suggesting that endogenous chitin is critical to barrier integrity. Protochordates, such as Ciona, retain basic characteristics found in other more advanced chordates and can inform us of uniquely conserved signals shaping host-microbiota interactions in the absence of adaptive immunity. These simpler model systems may also reveal factors and processes that modulate recovery from colitis, the role gut microbiota play in the onset of the disease, and the rules that help govern the reestablishment and maintenance of gut homeostasis.