Livers cultured with D-Gal plus LPS exhibited a significant decrease in IL-25 production (Supporting Fig. 2C). Together, these observations
indicate that induction of D-Gal/LPS-mediated liver damage is accompanied Midostaurin by decreased IL-25 production. Next, we examined whether IL-25 could prevent D-Gal/LPS-driven acute liver damage. Mice were pretreated IP with IL-25 or vehicle 1 hour before D-Gal/LPS administration; blood samples were collected 6 hours later and mice were sacrificed at hour 8. The dose of IL-25 we selected for this study was the same as that we previously used to suppress experimental colitis in mice.[9, 10, 12] As expected, serum levels of both alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were increased in D-Gal/LPS-injected
mice and IL-25 significantly reduced D-Gal/LPS-induced transaminases (Fig. 2A,B). Histopathology of liver sections showed severe organ damage in mice treated with D-Gal/LPS, characterized by a confluent hemorrhagic pattern, mononuclear cell infiltrate, and large areas of necrosis (Fig. 2C, left panel). Pretreatment with IL-25 reduced D-Gal/LPS-induced liver damage. In particular, mice receiving IL-25 showed less vessel congestion and reduced infiltration of the liver with inflammatory cells and minimal necrosis (Fig. 2C, left panels). TUNEL assay confirmed massive necrosis www.selleckchem.com/products/Temsirolimus.html of the liver in D-Gal/LPS-injected mice and the preventative effect exerted by IL-25 (Fig. 2C, right panels). In line with these data, western blotting showed activation of caspase-3 in total proteins extracted from mice treated with D-Gal/LPS, but not in proteins extracted from control or IL-25-treated D-Gal/LPS-injected mice (Fig. 2D). Because tumor necrosis factor alpha (TNF-α) NADPH-cytochrome-c2 reductase is involved in the pathogenesis of D-Gal/LPS-induced liver damage, we next assessed whether IL-25 reduced in vivo TNF-α expression. Pretreatment of mice with IL-25 significantly reduced D-Gal/LPS-induced TNF-α synthesis (Fig. 2E). Moreover, pretreatment of mice with IL-25 significantly reduced
D-Gal/LPS-induced IL-23p19 RNA expression (Supporting Fig. 3A), a cytokine known to be negatively regulated by IL-25. Induction of FH by D-Gal/LPS was associated with enhanced IL-17A, but not IL-22 expression (Supporting Fig. 3B,C). IL-25 did not reduce IL-17A induction (Supporting Fig. 3B). Although it has been previously shown that IL-25 reduces Th17 cell responses by suppression of IL-23, the reason why IL-17A was unchanged in IL-25-treated mice, despite down-regulation of IL-23, remains unknown. A possibility is that reduction of IL-23 in IL-25-treated mice occurred in a time frame (i.e., 6-8 hours) that was not sufficient to cause down-regulation of IL-17A. It is also conceivable that, in this model, IL-17A is produced by cell types (e.g.