Our previous studies have shown that ethanol intoxication combined with burn injury increases intestinal bacterial growth,disrupts the intestinal barrier,and enhances bacterial translocation. Additionally,studies show that Th17 effector cytokines IL-17 and IL-22,which are dependent on IL-23,play important roles in maintaining intestine mucosal barrier integrity. Recent findings suggest neutrophils are a significant source of IL-17 and IL-22. We determined the effect of ethanol and burn injury on neutrophil IL-17 and IL-22 production,as well as their ability to phagocytose and in bacterial clearance,and whether these effects are modulated by IL-23. Mice were given ethanol 4 h prior to receiving ˆ¼12.5% total body surface area burn and were euthanized day 1 after injury. We observed that intoxication combined with burn injury significantly decreases blood neutrophil phagocytosis and bacteria killing,as well as their ability to produce IL-17 and IL-22,compared with sham vehicle mice. The treatment of neutrophils with rIL-23 significantly increases IL-22 and IL-17 release and promotes expression of IL-23R,retinoic acid-related orphan receptor $\gamma$t,Lipocalin2,and Nod-like receptor 2 following ethanol and burn injury. Furthermore,IL-22- and IL-17-producing neutrophils have enhanced neutrophil extracellular trap formation and bacterial killing ability,which are dependent on IL-23. Finally,although we observed that peritoneal neutrophils harvested after casein treatment are functionally different from blood neutrophils,both blood and peritoneal neutrophils exhibited the same response to rIL-23 treatment. Together these findings suggest that IL-23 promotes neutrophil IL-22 and IL-17 production and their ability to kill bacteria following ethanol and burn injury.
View Publication