FIGURE 5.

PPARα regulates transcription of Th2 cytokine genes in a ligand-dependent manner. A, Splenocytes were isolated from a Vβ8.2 TCR transgenic B10.PL mouse and cultured in the presence of 100 μM gemfibrozil or vehicle control (EtOH). Cells were stimulated with or without MBP Ac1–11 for 48 h and crosslinked for ChIP. ChIP assays were performed using an Ab specific for PPARα and immunoprecipitated DNA was amplified using primers specific for the IL-4, IL-5, GATA3, and cMaf, promoter regions. B, Splenocytes were isolated as described in A and transfected with an siRNA specific for PPARα or an siRNA NS control. Cells were cultured in the presence of 100 μM gemfibrozil or vehicle control (EtOH) with or without MBP-Ac1–11 for 48 h and crosslinked for ChIP assays. ChIP assays were performed with a PPARα-specific Ab and immunoprecipitated DNA was amplified with primers specific for the IL-4 and IL-5 promoter regions that contained PPREs. C, Splenocytes were isolated and cultured as described in A. Cells were crosslinked for ChIP re-ChIP assay. ChIP re-ChIP was performed by immunoprecipitating first with a PPARα-specific Ab. Eluted immune complexes were then immunoprecipitated again using an Ab specific for SRC-1. Immunoprecipitated DNA was amplified using primers specific for the IL-4 promoter containing a PPRE. Results shown are representative of multiple experiments.