Figure 2.

The PPARγ agonist induces ANGPTL4 expression and secretion by promoting the binding of the PPARγ/RXRα heterodimer to its promoter. (a) Schematic representation of the ANGPTL4 gene promoter showing the location of the potential peroxisome proliferator-responsive elements (PPREs). (b) Chromatin immunoprecipitation (ChIP) assays were performed in HTR8/SVneo cells, HUVECs and placental explants using antibodies against PPARγ or IgG. Purified DNA was detected by qRT-PCR using primer sets specific to PPRE1-PPRE3 of ANGPTL4. The data are shown as the means±S.E.M. ***P<0.001 relative to IgG. (c–e) HTR8/SVneo cells, HUVECs and placental explants were transfected with control siRNA (si-Con) or RXRα siRNA (si-RXRα) and then stimulated with 1 μM rosiglitazone for 18 h. The mRNA and protein expression of PPARγ and ANGPTL4, the protein expression of RXRα and the secretion of ANGPTL4 were detected via qRT-PCR, western blot analysis and ELISA. The data are shown as the means±S.E.M. **P<0.01 versus control. (f) HUVECs, HTR8/SVneo cells and placental explants were transfected with si-Con or si-PPARγ and then treated with or without 1 μM rosiglitazone for 18 h. ChIP assays were accomplished with specific antibodies against PPARγ and RXRα