FIG. 5.

Txnip deletion augments PPARγ-stimulated adipogenesis and PPARγ activity. A: Wild-type and Txnip knockout adipocyte differentiation at day 9 after DMI induction + increasing rosiglitazone concentrations. Total lipid levels are quantified after ORO extraction at OD₅₂₀ staining. γ-antagonist = 1 μmol/l GW9229. *P < 0.001 for wild-type vs. Txnip knockout at each rosiglitazone concentration; n = 6 replicates per group. The representative color images were nonlinearly color-contrast enhanced using equivalent settings, and were not used for quantitative analysis. White bars = wild type, black bars = Txnip knockout. B: Endogenous PPARγ activation with increasing rosiglitazone dosing in 3T3-L1 cells stably transduced with Txnip or control lentivirus. PPARγ activity was determined by a transfected PPAR response element luciferase reporter stimulated by 18 h of rosiglitazone treatment (48 h after transfection). Transfection efficiency was normalized to β-galactosidase (β-gal) activity from a cotransfected β-gal reporter. n = 4 replicates per group. C and D: PPARγ LBD activation assay. PPARγ-LBD::GAL4 DNA-BD fusion protein was cotransfected with a GAL4 promoter-luciferase reporter into 3T3-L1 preadipocytes expressing Txnip lentivirus (C) or Txnip shRNA lentivirus (D) compared with relevant controls. Luciferase activity was determined after 18-h rosiglitazone stimulation. Transfection efficiency was normalized to β-gal activity from a cotransfected β-gal reporter. *P < 0.05, n = 4 replicates per condition. Graphs depict single representative experiments with error bars reflecting replicates. antag, antagonist. (A high-quality digital color representation of this figure is available in the online issue.)