17-19 miR-33 has also been shown to regulate fatty acid oxidation in hepatic cell lines.20 Nevertheless, despite these important advances, the full extent of posttranscriptional control of lipid metabolism by miRNAs remains incompletely understood and has not been systematically investigated.21 Using an unbiased in silico approach, which should be generally applicable toward the identification of key regulatory miRNAs in any biological process, we predicted miR-27b as a regulatory hub in lipid metabolism. Furthermore, we demonstrated that hepatic miR-27b is responsive to lipid levels and regulates the expression

(messenger RNA [mRNA] and protein) of key metabolic genes, including angiopoietin-like 3 (ANGPTL3) and glycerol-3-phosphate acyltransferase 1 (GPAM), which have been implicated previously in the pathobiology LEE011 price of lipid-related disorders. ELISA, enzyme-linked immunosorbent assay; FDR, false-discovery rate; HFD, high-fat diet; miRNAs, Doxorubicin microRNAs; ORF, open reading frame; PCR, polymerase chain reaction; UTRs, untranslated regions. Eight-week-old wildtype C57BL/6J mice were placed on either normal chow diet (4% fat, NIH-31 open chow, Zeigler Brothers, Gardners, PA) or a high-fat Western

diet (21% fat, 42% calories from fat, ad libitum, TD88137, Harlan-Teklad, Frederick, MD) for 3 weeks (19-21 days). Adult (8-10 weeks) female apolipoprotein E null mice (Apoe−/−, C57BL/6J background; Jackson Laboratory, Bar Harbor, ME) were placed on either normal chow or cocoa butter diet with sodium cholate (16% fat, 37% calories from fat, 1.25% cholesterol, 0.125% choline chloride, 0.5% sodium cholate, TD90221, Harlan-Teklad) for 4 weeks (28 days). Mouse livers were excised and homogenized (100 mg) in Qiazol Total RNA extraction buffer. All mice were housed and the relevant studies

were completed under active protocols approved by the National Institutes of Health, National Heart, Lung, 上海皓元医药股份有限公司 and Blood Institute Animal Care and Use Committee. All protocols complied with, and all animals received humane care according to, the criteria outlined in the NIH “Guide for the Care and Use of Laboratory Animals. miRNA isolation and Illumina sequencing were completed as reported.22 Details are provided in the Supporting Methods. Target sites (seed, centered) were predicted for miR-27b in both the 3′ untranslated regions (UTRs) and the open reading frames of the 151 lipid metabolism genes. Details of target site prediction and the identification of candidate miRNA regulatory hubs by Monte Carlo simulations are provided in the Supporting Methods. Human hepatocytes (Huh7) were cultured in F12 Dulbecco’s modified Eagle’s medium (DMEM), supplemented with 10% fetal bovine serum, penicillin (100 U/mL), and streptomycin (100 μg/mL), and maintained at 37°C with 5% CO2.