Treatment with broad-spectrum antibiotics after the initial ConA injection resulted in less TGF-β-producing CD11c+ DC migration into the liver. CONCLUSIONS: The TLR9 pathway plays a distinct role in immune activation and tolerance in murine acute hepatitis.

Severity of hepatic injuries and changes in intestinal bacterial flora might regulate the balance between immunity and tolerance through TLR9 in a time-dependent manner. Compound Library research buy Disclosures: The following people have nothing to disclose: Nobuhiro Nakamoto, Hirotoshi Ebinuma, Nobuhito Taniki, Yuko Wakayama, Po-sung Chu, Akihiro Yamaguchi, Takeru Amiya, Hidetsugu Saito, Takanori Kanai Impaired vascular regulation contributes to liver injury in hepatic pathologies including sepsis/inflammation. Sinusoidal endothelial cell dysfunction is a major cause in sepsis; however, the mechanisms are not fully understood. Sonic hedgehog (shh) in microparticles

(MP) has been shown to modulate liver injury. Since sepsis is associated with T cell apoptosis and apoptotic T cells shed (MP) containing shh, we tested whether MP from apoptotic T cells might modulate endothelial function. MPs containing shh (confirmed by Western blot) were produced by inducing apoptosis in human CEM T cell line. Human umbilical vein endothelial cells (HUVEC) were used as a model. We first tested the effect of MP on endothelin (ET)-stimulated eNOS. ET increased eNOS activity and this was inhibited by endotoxin (LPS). Pretreatment with MP alone resulted MCE in a more than 2x increase in ET-stimulated eNOS activity. However, see more with MP + LPS, ET-stimulated eNOS was inhibited even more than with LPS alone, indicating an interaction between LPS and MP. We next tested the effect of MP on HUVEC wound healing / proliferation.

Without MP pretreatment 74 +/− 4 % of the wound healed at 12 hours; with MP, only 44% healed. This was duplicated using the smoothened activator purmorphamine (Pur, 43% p<.05) indicating a role for shh. We next tested whether MP affected the response to oxidative stress. HUVECS were pretreated for 6 or 24 hours with MP followed by two hours of H2O2 or cotreatment with MP and H2O2. Viability was assessed by MTT. H2O2 alone caused no significant loss of viability, but it was decreased by 40% to 75% with each treatment indicating that MP sensitize to oxidative stress. Finally, we tested the effect of MP on morphology. Untreated cells showed a typical cobblestone appearance. MP resulted in a more elongated, spindle-shape. Aspect ratio (long axis/ short axis) for untreated was 2.4 +/− 0.1 and with MP, 3.9 +/− .24 (p< .001). This was duplicated by Pur indicating implicating shh. While the canonical pathway for shh involves gli, we were unable to demonstrate gli induction by MP or Pur. Shh may activate rho kinase in endothelial cells.