TRAIL−/− mice were significantly protected against ConA-hepatitis compared to WT mice as depicted by serum transaminases levels (Fig. 4A; Fig. S4A). A significant difference in liver IL-33 mRNA expression was observed between WT and TRAIL−/− mice. The up-regulation IL-33 expression was significantly reduced in TRAIL−/− livers MS-275 nmr (Fig. 4B). Histopathology of liver tissues revealed perivascular and parenchymal zones of liver injury in TRAIL−/− and WT mice (Fig. 4C). Interestingly, only few hepatocytes were positive for IL-33 in TRAIL−/− livers compared with WT mice (Fig. 4D). Following ConA-hepatitis, we observed increased liver mRNA expression for TRAIL, DR5, FasL, and Fas but not for TNFR1 or TNFR2 in

WT mice at different time intervals (Fig. S4B). Localization of the DR5 receptor was further addressed in WT mice by immunohistochemistry showing DR5 receptor expression dominantly in noninjured liver areas, whereas low DR5 expression was evident in necrotic areas (Fig. S4C). Moreover, the expression of hepatocyte-specific nuclear IL-33 and membrane DR5 expression was selectively colocalized in the noninjured area of liver (Fig. S4C). WT and TRAIL−/− mice showed no significant difference in the regulation of liver DR5, TNFR1, and TNFR2 mRNA expression before and 10 hours after ConA

injection (Fig. S4D). However, a significant increase in liver FasL mRNA expression was observed in TRAIL−/− mice compared to WT mice 10 hours after ConA injection, whereas liver Fas and TNFα mRNA levels were significantly down-regulated in TRAIL−/− find more compared to WT mice at this timepoint (Fig. S4D). To address the functional click here role of IL-33 in ConA liver injury, we compared hepatic injury in WT and IL-33-deficient

mice. We demonstrated significantly increased levels of serum ALT in IL-33−/− mice than WT controls at 24 hours of ConA liver injury, suggesting a protective effect of IL-33 during ConA-hepatitis (Fig. 4E). To test an essential role of TRAIL for inducing IL-33 expression in hepatocytes, we reconstituted CD1d−/− mice (NKT cells deficient) with rm-TRAIL following ConA-priming. There was no significant difference in basal TRAIL mRNA expression between WT and CD1d−/− livers (Fig. 5A). However, after ConA injection liver mRNA TRAIL expression was significantly lowered in CD1d−/− compared to WT mice (Fig. 5A). Additionally, the kinetic of higher liver DR5 mRNA expression after ConA administration was also significantly less evident in CD1d−/− compared to WT livers (Fig. 5B). We next tested the possibility of whether TRAIL administration after ConA injection was able to induce liver injury in CD1d−/− mice. The simultaneous injection of TRAIL and ConA in CD1d−/− mice significantly induced stronger liver injury as evidenced by increased serum ALT and AST levels in the ConA/TRAIL- compared to the ConA/PBS-treated group (Fig. 5C; Fig. S5).