Native and post-translationally modified HMGB1 were detected in human and in mice with alcoholic liver disease. In liver and in serum from control mice and in serum from healthy volunteers, the lysine residues within the peptides containing nuclear localization signals-1

and 2 were non-acetylated and all cysteine residues were reduced. However, in livers from ethanol-fed mice, in addition to all thiol/non-acetylated isoforms of HMGB1, we observed acetylated nuclear localization signals-1 and 2, a unique phosphorylation site in serine 35 and an increase in oxidation of HMGB1 to the disulfide isoform. In serum from ethanol-fed mice and from patients with alcoholic liver disease there Selleck CHIR-99021 was disulphide bonded hyper-acetylated-HMGB1, disulphide bonded non-acetylated-HMGB1 and HMGB1 phos-phorylated in serine 35. Hepatocytes appeared to be a major source of these HMGB1 isoforms. Conclusion: Hepatocyte HMGB1 participates in the pathogenesis of alcoholic liver disease and undergoes post-translational modifications that could condition its

toxic effects. Disclosures: Andrea D. Branch – Grant/Research Support: Kadmon, Gilead, Janssen The following people have nothing to disclose: Xiaodong Ge, Daniel J. Antoine, Yongke Lu, Elena Arriazu, Tung Ming Leung, Arielle L. Klepper, M. Isabel Fiel, Natalia Nieto Background: Chronic alcohol consumption leads to hepatic ste-atosis. The molecular mechanisms of lipid accumulation have been Selleck SCH727965 selleckchem primarily investigated in hepatocytes, while the roles of neighboring cells in this process have been less explored. Nogo-B (a.k.a., Reticulon 4B) is an endoplasmic reticulum resident protein and plays important roles in pathological conditions in

various tissues. In the liver, Nogo-B is expressed in non-parenchymal cells including Kupffer cells, but not in hepatocytes, and promotes liver fibrosis. Given that Kupffer cells play a role in hepatic steatosis in a paracrine manner, we hypothesize that Nogo-B may contribute to ethanol-in-duced steatosis by modulating Kupffer cell function. Methods: Wild-type (WT) or Nogo-B knockout (KO) mice were fed with control or Lieber-DeCarli ethanol liquid diets (5% ethanol) for 6 weeks. Lipopolysaccharide (LPS) was injected intraperito-neally 9 hours before sample collection. For in vitro studies, Kupffer cells were isolated from WT and KO mice and treated with 0 or 100 mM ethanol in the presence or absence of LPS. Results: Lipid accumulation was significantly reduced in livers of Nogo-B KO mice fed with ethanol diet, compared to WT mice (hepatic triglyceride levels: 10+/−2 vs. 28+/−4 mg/g liver, p<0.01; steatosis score: 0.8+/−0.1 vs. 2.0+/−0.3, p<0.05). A histological score showed a trend toward reduced inflammation in KO livers, compared to WT livers (p=0.07), and was associated with decreased infiltration of neutrophils (p<0.