Figure 6.

Wnt proteins secreted by myeloid cells upon α-galactosylceramide (α-GalCer) challenge regulate the interferon gamma (IFN-γ) response. (A) Mice with a conditional knockout of Wls (Wls^fl/fl LysM-Cre⁺) and littermate controls (Wls^fl/fl LysM-Cre⁻) were challenged with α-GalCer. Percentages of CD3⁺NK1.1⁺ natural killer T (NKT) cells expressing IFN-γ in the liver, and the serum levels of IFN-γ were analyzed. Data are means ± SEM of four to six mice per genotype (n = 2 for 4.5 h Wls^fl/fl LysM-Cre⁻ group) per time point cumulatively analyzed in four independent experiments. (B) Percentages of CD3⁺NK1.1⁺ NKT cells expressing IFN-γ was determined by flow cytometry in mice treated with DMSO or the Porcupine inhibitor, IWP2. Data are means ± SEM of four to nine mice per treatment for each time point from two to three independent experiments. At each time point, groups in panels (A,B) were compared using unpaired two-sided t-test; *p < 0.05. (C) Mircoarray-based gene expression analyses of sorted CD4⁻ (and CD8-negative, DN) and CD4⁺ liver NKT cells were analyzed for the expression of Wnt signaling components. Data are presented as mean ± SEM. The threshold was set at the expression level of Il12a, which is not expressed by NKT cells.