Mice were depleted exclusively

of plasmacytoid DC using 120G8 before APAP challenge. However, plasmacytoid DC depletion Carfilzomib molecular weight did not exacerbate APAP liver toxicity (Supporting Fig. 4). Similarly, we tested whether activation of the aryl hydrocarbon receptor on DC, which inhibits liver DC maturation in vivo and mitigates their ability to induce adaptive Th2 responses27, 30 (Supporting Fig. 5A,B), would also lead in exacerbated injury when administered to APAP-challenged mice. However, VAG539 did not modulate APAP toxicity (Supporting Fig. 5C-E). Because the absence of DC results in exacerbated APAP-mediated injury, we interrogated the immune-phenotype of DC in animals challenged with APAP. Both the absolute number and fraction of liver DC among hepatic leukocytes did not change after APAP challenge (Fig.

3A,B); however, DC underwent an increase in maturation and alteration in subset composition in acute APAP hepatotoxicity (Fig. 3C). In particular, DC harvested from APAP-injured liver had elevated expression of MHC II and CD86, exhibited AZD4547 datasheet a lower B220+ plasmacytoid fraction, and underwent a “myeloid shift” expressing higher CD11b and lower CD8 (Fig. 3C). Conversely, spleen DC phenotype was unchanged after APAP challenge (Fig. 3C). Liver DC also increased their expression of Toll-like receptor (TLR)2, TLR4, TLR7, and TLR9 after APAP challenge (Supporting Fig. 6A). However, there was no measurable increase in selected byproducts of sterile inflammation in APAP-DC liver compared with APAP alone (Supporting Fig. 6B,C). In addition to an altered surface phenotype, the

immunogenicity of DC harvested from the APAP injured liver was altered as DC from APAP liver produced higher IL-6, MCP-1, and TNF-α (Fig. 3D) compared with liver DC from saline-treated mice. Furthermore, consistent with their increased TLR expression, liver DC had an exaggerated cytokine response to TLR ligation after APAP toxicity (Fig. 3E). Spleen DC did not produce altered levels of cytokines after APAP challenge (not shown). Despite changes in hepatic DC surface phenotype and cytokine production after APAP challenge, their capacity to stimulate antigen-restricted CD4+ and CD8+ T cells was not medchemexpress enhanced (Fig. 3F). Because DC depletion exacerbates APAP-mediated hepatotoxicity, we postulated that expansion of DC populations would mitigate liver injury. To test this, we employed Flt3L, which we have previously shown expands DC populations in vivo more than 10-fold.31, 32 Mice were treated with Flt3L for 10 days before APAP challenge followed by sacrifice at 12 hours. Notably, the maturation level of liver DC in Flt3L-treated mice was similar to controls except for a greater fraction of B220+ plasmacytoid DC in the Flt3L-treated group (Supporting Fig. 7A,B). However, after APAP treatment the fractions of plasmacytoid DCs were similar in both the Flt3L + APAP and in the APAP-only group (Supporting Fig. 7B).