IL-4Rα-mediated STAT6 signaling is critical for IL-13-induced IL-31RA expression.
A, peritoneal macrophages from wild-type C57BL/6 and IL-4Rα KO mice were stimulated with IL-13 (10 ng/ml) for 24 h, and IL-31RA expression was measured by quantitative RT-PCR. Data are representative of two independent experiments and expressed as mean ± S.E. ***, p < 0.001. B, peritoneal macrophages from wild-type and STAT6 KO mice were stimulated with IL-13, and IL-31RA transcripts were measured by quantitative RT-PCR. Data are representative of two independent experiments and expressed as mean ± S.E. ***, p < 0.001. C, schematic representation of the mouse IL-31RA gene showing the location of the putative STAT6 binding sites. Open boxes indicate untranslated regions followed by coding sequence (exon). Sequences of STAT6 are represented by black boxes and their respective binding sites are indicated. D, peritoneal macrophages from wild-type mice were cultured with IL-4 (10 ng/ml) for 2 h. Cell lysates were prepared, and the ChIP assay was performed with PCR using anti-STAT6 antibody and normal rabbit IgG as a negative control. Non-immunoprecipitated DNA is represented as Input DNA. Data are representative of two independent experiments.