Journal:

Article Title: Foxo1 mediates insulin action on apoC-III and triglyceride metabolism

doi: 10.1172/JCI200419992

Figure Lengend Snippet: Effects of Foxo1 on hepatic apoC-III expression. Rat primary hepatocytes were transduced with Foxo1 or LacZ vector at an MOI of 50 PFU/cell or mock-transduced with PBS. After 24 hours of transduction, the intracellular levels of apoC-III (A), Foxo1 (B), and GK (C) mRNA were determined by real-time RT-PCR using β-actin mRNA as control. The effect of Foxo1 on hepatic apoC-III expression in response to insulin was assayed in HepG2 cells. Cells were transduced with Foxo1, Foxo1-ADA, or control LacZ vector (50 PFU/cell) in the absence or presence of insulin at different concentrations. Twenty-four hours after transduction, cells were collected for determination of the intracellular levels of apoC-III mRNA induced by Foxo1 (D) and Foxo1-ADA (E). *P < 0.05, **P < 0.005; significantly different from controls. NS, not significant by ANOVA. Data were from 3 independent experiments.

Article Snippet: As controls, aliquots (1 × 10 6 ) of Foxo1 vector–transduced HepG2 cells were treated identically for the preparation of cell lysates, which were immunoprecipitated with 5 μg of control IgG (sheep IgG, Rockland Immunochemicals) or PBS buffer.

Techniques: Expressing, Transduction, Plasmid Preparation, Quantitative RT-PCR

Journal:

Article Title: Foxo1 mediates insulin action on apoC-III and triglyceride metabolism

doi: 10.1172/JCI200419992

Figure Lengend Snippet: Effects of Foxo1 on the human APOC3 promoter activity. (A) The APOC-III promoter–directed luciferase reporter system. The wild-type and mutant IRE sequences are underlined. (B) Foxo1-mediated induction of the APOC3 promoter activity. HepG2 cells were transfected by pHD317 together with Foxo1 construct, or with both Foxo1 and Foxo1-Ø256 constructs. For each construct, 1 μg of DNA for each construct was used in transfection. For normalization of transfection efficiency, 1 μg pCMV5-LacZ DNA was included for normalization of transfection efficiency. (C) The APOC3 promoter variants in the luciferase reporter system. (D) Responses of APOC3 promoter variants to Foxo1 production. HepG2 cells were transfected with individual test plasmids in the absence (–) or presence (+) of pCMV5-Foxo1. The relative luciferase activity, after normalizing to β-gal activity, was compared between basal (–) and Foxo1-inducible (+) conditions. (E) Responses of wild-type and mutant APOC3 promoters to insulin. Test plasmids were transduced into HepG2 cells in the presence and absence of pCMV5-Foxo1 transfection in culture media, either supplemented with or without insulin (30 nM). The relative luciferase activity in transduced cells was determined using β-gal activity as control. *P < 0.001 vs. controls.

Article Snippet: As controls, aliquots (1 × 10 6 ) of Foxo1 vector–transduced HepG2 cells were treated identically for the preparation of cell lysates, which were immunoprecipitated with 5 μg of control IgG (sheep IgG, Rockland Immunochemicals) or PBS buffer.

Techniques: Activity Assay, Luciferase, Mutagenesis, Transfection, Construct

Journal:

Article Title: Foxo1 mediates insulin action on apoC-III and triglyceride metabolism

doi: 10.1172/JCI200419992

Figure Lengend Snippet: Molecular interaction between Foxo1 and the APOC3 promoter. Molecular association between Foxo1 and the APOC3 promoter was analyzed by EMSA and ChIP. Aliquots of Foxo1 protein from linked in vitro transcription-translation products (5 μg) were incubated with 2.5 μl of radioactively labeled DNA corresponding to –467/–440 nt in the human APOC3 promoter (WT-IRE) (A), a mutant APOC3 IRE (mt-IRE) containing 2 substitutions, of –A458C and –A460G, and a control PEPCK IRE DNA (B), followed by electrophoresis through 8% nondenaturing polyacrylamide gels for 30 minutes. Lane 1, DNA probe alone. Lane 2, DNA probe + Foxo1 protein lysates. Lane 3, DNA probe + Foxo1 protein lysates + anti-Foxo1 antibody (1 μg). Lane 4, DNA probe + Foxo1 protein lysates + nonlabeled competitor DNA at a molar concentration of 50-fold excess. Free, shifted, and supershifted DNA bands were visualized by autoradiography. For ChIP assay, HepG2 cells were transduced with Foxo1 vector at an MOI of 50 PFU/cell. Cells were harvested 24 hours later and subjected to ChIP using PBS as a negative control (lane 5), control IgG (lane 6), and anti-Foxo1 antibody (lane 7). The coimmunoprecipitated chromatin DNA was analyzed by immunoblot (C) using anti-Foxo1 antibody and PCR (D) using the primers that correspond to –655/–20 nt of the APOC3 promoter.

Article Snippet: As controls, aliquots (1 × 10 6 ) of Foxo1 vector–transduced HepG2 cells were treated identically for the preparation of cell lysates, which were immunoprecipitated with 5 μg of control IgG (sheep IgG, Rockland Immunochemicals) or PBS buffer.

Techniques: In Vitro, Incubation, Labeling, Mutagenesis, Electrophoresis, Concentration Assay, Autoradiography, Transduction, Plasmid Preparation, Negative Control, Western Blot