7G). Unfortunately, by 6 hours a majority of Lys-Cre Ron TKfl/fl mice were moribund or dead and adequate blood could not be collected for ALT analysis. Importantly, however, at 6 hours ALT levels in Ron TKfl/fl control plasma were significantly higher than Alb-Cre Ron TKfl/fl plasma, suggesting protection of the TK−/− hepatocytes. TUNEL staining was PD-1 antibody inhibitor performed on liver sections at 5 hours to assess the level of apoptosis (Fig. 7D-F). Alb-Cre Ron TKfl/fl liver had statistically lower levels of TUNEL-positive cells followed by control Ron TKfl/fl and Lys-Cre Ron TKfl/fl livers (Fig. 7H). This result is consistent with western analyses for active (cleaved) caspase-3 observed

in liver lysates with the lowest levels of active caspase-3 detected in the Alb-Cre Ron TKfl/fl livers (Supporting Information Fig. S2). To test for survival differences, mice from each group were allowed to proceed until death Buparlisib mw from ALF. Kaplan-Meier survival curves (Fig. 8A) clearly show that Lys-Cre Ron TKfl/fl mice have a significantly shorter survival time. The mean survival time of each genotype is depicted

in Fig. 8B. Although Fig. 7 demonstrates protection from hepatocyte apoptosis and liver injury in the Alb-Cre Ron TKfl/fl mice compared to the other genotypes, overt survival of the Alb-Cre Ron TKfl/fl mice was longer than the Ron TKfl/fl mice but was not statistically different (P = 0.07). Here we dissected the role of Ron receptor TK in an endotoxin-induced model of acute liver failure to further studies

demonstrating that mice with a global deletion of Ron TK had a protected liver injury phenotype.16 Examination of hepatocytes and Kupffer cells showed expression of Ron in both, and importantly, ex vivo experiments showed Ron signaling is critical for both suppressing hepatotoxic Kupffer cell cytokine production and for sensitizing hepatocytes to Kupffer cell-derived products such as TNF-α. Together with in vivo experiments using mice with either hepatocyte- or Kupffer cell-specific deletion of Ron TK, we determined STK38 that Ron TK signaling in both cell types has important effects on hepatocyte survival following exposure to endotoxin in this model of acute liver failure. However, the cell type likely responsible for Ron-dependent hepatic protection in this liver injury model is the hepatocyte, given that lack of Ron signaling in hepatocytes ex vivo and in vivo is sufficient to afford a hepatocyte survival benefit. Following stimulation with LPS, TK−/− Kupffer cells have altered cytokine production ex vivo compared to TK+/+ Kupffer cells, with the most significantly elevated cytokines being IL-1ra (2.5-fold), IL-6 (2-fold), TIMP-1 (1.5-fold), MCP-1 (3.5-fold), and MIP-2 (1.9-fold). A potential mechanism for these perturbations is increased NF-κB signaling in the Ron-deficient state.