Our findings reveal that dysregulation of miRNA-122 (miR-122) contributes to hepatic insulin resistance through PTP1B induction. Flavonoids are being actively studied Selleck Ivacaftor as potential treatments for components of the metabolic syndrome. In our previous study, treatment with licorice flavonoid ameliorated liver steatosis.12 In the present study, we additionally discovered the effect of c-Jun

N-terminal kinase 1 (JNK1) inhibition by isoliquiritigenin (IsoLQ) or liquiritigenin (LQ) on miR-122 dysregulation using in vivo models and cell-based assays. Here, we report that they have the ability to abolish hepatic insulin resistance by recovering the constitutive expression of miR-122 responsible

for PTP1B down-regulation. Information on the materials used in this study is described in the Supporting Information. Animal studies were conducted in accordance with the guidelines of the Institutional Autophagy inhibitor Animal Use and Care Committee. Male C57BL/6 mice at 6 weeks of age were started on a high-fat diet (HFD) for 11 weeks. Detailed information is provided in the Supporting Information. HepG2, H4IIE, C2C12, and 3T3-L1 cell lines were purchased from the American Type Culture Collection (ATCC, Rockville, MD). The isolation of primary rat hepatocytes is described in the Supporting Information. The plasmid containing Luc-PTP1B-3′UTR (3′-untranslated region; Product ID: HmiT015828-MT01) was specifically synthesized (GeneCopoeia, Rockville, MD) and was used in luciferase reporter assay. The plasmid contains firefly luciferase fused to the 3′UTR of human PTP1B, and Renilla luciferase that functions as a tracking gene. pMiR-122a luciferase reporter vector containing the firefly luciferase gene and miR-122 target site at 3′UTR was purchased from Signosis (Sunnyvale, CA). When

miR-122 is expressed, it binds to the sequence and results in repression of the luciferase gene. The sources of other vectors and procedures used in this study for transient transfections and reporter gene assays are provided in the Supporting Information. Total 上海皓元医药股份有限公司 RNA was extracted with TRIzol (Invitrogen, Carlsbad, CA) and was reverse-transcribed. Quantitative real-time PCR (qRT-PCR) was performed with the Light Cycler 1.5 (Roche, Mannheim, Germany). Chromatin immunoprecipitation assay was done using the EZ ChIP kit (Upstate Biotechnology, Lake Placid, NY) according to the manufacturer’s protocol. HFD feeding increased the mRNA and protein levels of PTP1B (Fig. 1A); the change in the level of PTP1B protein was greater than that in its mRNA, suggesting that a posttranscriptional mechanism might be involved in this event. RNA22 and TargetScan programs enabled us to select miRNAs that potentially bind to the 3′-untranslated region (3′UTR) of PTP1B (PTPN1) mRNA (Fig.