Disclosures: Cytoskeletal Signaling inhibitor The following people have nothing to disclose: Douglas A. Simonetto, Vikas K. Verma, Jung Hee Kwon, Usman Yaqoob, Thiago de Assuncao, Sheng Cao, Tatiana Kisseleva, David A. Brenner, Vijay Shah [Purpose] Chronic alcohol consumption is a major public health problem that frequently leads to the development of liver steato-sis, fibrosis, and eventually cirrhosis and hepatocellular carcinoma. Hyperhomocysteinemia is a pathological consequence of alcoholic liver disease (ALD) and is attributed to insulin resistance. However, the regulatory function
of nuclear receptors in ALD associated with dysregulation of methionine metabolism remains largely unknown. This study revealed for the first time a critical role of the small learn more heterodimer partner (SHP, NR0B2) in alcohol-induced hyperhomocysteinemia that is mediated by the liver circadian clock. [Methods] The chronic and binge eth-anol-feeding model was established using male wild-type (WT) and Shp−/− mice (Nat Protoc 2013;8:627-637). Briefly, the mice were randomly assigned to control (CTRL) or ethanol-fed (EtOH) groups. The EtOH group was fed the Lieber-DeCarli diet containing 5% ethanol ad libitum. After ten days, the mice were orally administered maltose dextrin solution (CTRL) or ethanol solution (5 g of ethanol/kg
of body weight). Nine hours after the binge, the mice were sacrificed every 6 hours for 24 hours. Serum and livers were collected Reverse transcriptase at each time point. [Results] Ethanol-binge feeding resulted in hyperhomo-cysteinemia in WT mice in a circadian clock-mediated fashion, which was prevented in Shp−/− mice, as revealed by GS-MS analysis. The key enzymes that control methionine catabolism, including Bhmt and Cth, were strongly upregulated in control and alcohol-fed Shp−/− liver compared to WT liver. In addition, homocysteine-feeding induced glucose intolerance in WT mice, which was abrogated in Shp−/− mice. ER stress markers, including p-Ire1 a and p-Perk, were induced by homocysteine in
WT mice, which was largely attenuated in Shp−/− mice. Interestingly, ethanol-binge decreased protein levels of ER stress markers p-Ire1 a and Chop in WT and Shp−/− mice, whereas Chop expression was strikingly elevated in Shp−/− liver. We found that Rev-erba markedly induced Chop promote activity, which was decreased by alcohol treatment and diminished by Shp expression. Rora also induced Chop expression through ROR-binding site in mouse Chop promoter which was suppressed by ethanol treatment. [Conclusions] Our study elucidated a new molecular pathway by which SHP modulates ethanol-binge-induced hyperhomocysteinemia and ER stress involving Rer-Erba and Rora. Our observation provides novel insights into circadian regulation of alcoholic liver diseases. [Grant support] NIH DK080440, AHA 13GRNT14700043, VA Merit Award 1I01BX002634.