Figure 5.
4-phenylbutyric acid (4-PBA) promotes the expression of CD24 through enhanced PPARγ (peroxisome proliferator-activated receptor γ) activation in a Tollip-dependent manner. Bone marrow–derived monocytes (BMMs) from wild-type (WT) C57 BL/6 mice and Tollip−/− mice were cultured in vitro with M-CSF (macrophage colony-stimulating factor; 10 ng/mL) in the presence of 4-PBA (1 mmol/L) or PBS for 5 days. A, Cell lysate was isolated and subjected to immunoprecipitation with anti-NEDD8 antibodies conjugated to resin. The association of PPARγ with NEDD8 was examined by Western blotting. PPARγ in cell lysate was also examined by Western blotting. B, Surface expression of CD24 on CD11b+ Ly6G− Ly6Chi monocytes was examined by flow cytometry. Mean Fluorescence Intensity (MFI) of CD24 was quantified. Data in B were analyzed using 2-way ANOVA followed by Šídák post hoc test (n=5 for each group; biological replicates). Error bars represent means±SEM.