The Colonic Cytokine Environment Found During Brachyspira hyodysenteriae Infection Induces Mucus Changes in a Mucus Secreting, Polarized In Vitro Colonic Mucosal Surface

Brachyspira hyodysenteriae colonizes the pig colon and causes swine dysentery. We have previously shown that B. hyodysenteriae infection causes changes in the mucin environment characterized by a disorganized mucus structure and a massive mucus induction with de novo expression of MUC5AC and increased expression of MUC2 in the colon, which increases the B. hyodysenteriae binding ability to mucus. The aims of the present study were to determine how the cytokine environment changes in the pig colon during infection, and identify which of these changes are important for mucin production. The cytokine profile in the colon of B. hyodysenteriae infected pigs was characterized by increased expression of IL-1β, IL-6 and IL-8. Mucus producing in vitro colonic mucosal surfaces were stimulated with these cytokines, with and without B. hyodysenteriae infection, and mucin type, production rate and turn over were determined. Preliminary data show that the combined effect of these cytokines during infection increased the proportion of MUC2 and MUC5AC secreting goblet cells in the in vitro mucosal surface, and increased the mucin turn over rate. Overall, our data suggest that the upregulation of factors from the immune system is at least partly responsible for the mucus induction during B. hyodysenteriae infection.