Figure 2.

IL-13 signaling mechanisms and associated host directed targets in the treatment of ulcerative colitis. IL-13 signals through the type II (IL-4Rα and IL-13Rα1) receptor complex and activates the JAK1/STAT6 pathway. In addition, IL-13 has also been shown to signal through IL-13Rα2, activating AP-1 to induce the secretion of TGF-β. This pathway is, in part dependent on the production of TNFα. Various drug targets have been directed at IL-13 including the IL-4Rα signaling pathway to block the immune response that mediate Th2-driven inflammatory diseases such as allergy and colitis. Drug treatments that were beneficial or improved disease outcome are depicted in green and treatments that were unsuccessful or exacerbated disease outcome are depicted in red (Rutgeerts et al., 2005; Wenzel et al., 2007; Levin and Shibolet, 2008; Reinisch et al., 2011, 2015; Mannon and Reinisch, 2012; Sandborn et al., 2012; Verma et al., 2013; Colombel et al., 2014; Feagan et al., 2014; Danese et al., 2015; Palamides et al., 2016; Hoving et al., 2017; Popovic et al., 2017).