Fig. 3: The expression of genes encoding PGE₂-synthesizing enzymes and IL-22BP is regulated by Dectin-1 signaling.

a–d GF WT and Clec7a^−/− mice treated with AOM-3DSS shown in Fig. 1m were sacrificed at 36 weeks after AOM administration, and RNA-seq analysis was carried out by using RNAs from polyps and non-polyp tissues in the vicinity (pooled 4 WT and 5 Clec7a^−/− GF mice). Expression levels of genes for cytokine, chemokine, cell-surface marker, and T cell transcription factor in WT and Clec7a^−/− mice are shown as heatmaps (a). Cell populations, signaling pathways and metabolic pathways were compared between Clec7a^−/− and WT mouse polyps by using the KEGG database. Log2 (fold-change) > 1 is upregulated genes, while log2 (fold-change) <−1 is downregulated genes (b). Expression levels of MDSC-associated genes are presented as a heatmap (c). Expression levels of PGE₂-synthase genes in polyp and non-polyp tissues are shown as a heatmap (d). e–h SPF WT and Clec7a^−/− mice treated with AOM-3DSS for 16 weeks, and CD11b⁺ and CD11c⁺ cells were purified from colorectal polyps and were applied to scRNA-seq analysis. UMAP showing cell type cluster distribution (e), proportions of MDSC and DC subsets (f), changes of typical MDSC-associated gene expressions during MDSC development (g), and the trajectory tracks of the differentiation of PMN-MDSCs and M-MDSCs (h) in WT and Clec7a^−/− mice are shown (5 WT and 4 Clec7a^−/− mice pooled). i Bone marrow cells from WT mice were harvested and were stimulated with rGM-CSF and rIL-6 (2 × 10⁵ cells/well) for 5 days. Curdlan with indicated doses was added on the 2nd day and flow cytometry was carried out to examine MDSC differentiation by staining with antibodies against Ly6C and CD11b. j After the culture in i, differentiated bone marrow cells were further co-cultured with splenic CD4⁺ T cells from WT mice for 2 days in the present of anti-CD3/CD28 microbeads. After the co-culture, proportions of CD11b⁺ and CD4⁺ cells in CD45⁺ cells and the proportion of IFN-γ⁺ cells in CD4⁺ cells were determined by flow cytometry (n = 3 biologically independent samples/group; in CD11b⁺ panel, ***P = 0.0009; in CD4⁺ T panel, ****P < 0.0001; in IFN-γ⁺ panel, ***P = 0.0001). k EpCAM⁻MHC-II⁻Gr1⁺ cells were isolated from colonic polyps of AOM-3DSS-treated WT and Clec7a^−/− mice and were co-cultured with splenic CD4⁺ T cells in the presence of anti-CD3/CD28 microbeads. Two days later, flow cytometry was carried out to determine the number of live CD4⁺ T cells (control n = 3, +WT MDSC n = 5, + Clec7a^−/− MDSC n = 3, ****P < 0.0001). l Intestinal polyp-infiltrating cells were isolated from Apc^Min/+ and Apc^Min/+Clec7a^–/– mice, and proportions of NOS2-producing CD11c^–CD11b⁺ cells were determined by flow cytometry (Apc^Min/+ n = 6, Apc^Min/+Clec7a^−/− n = 7, **P = 0.0027). Data in i, j are representatives of three and in k is representative of two independent experiments. Data from two independent experiments are pooled in l and in j–l are expressed as means ± SD. Data in j, k are analyzed using one-way ANOVA followed by Tukey’s multiple-comparisons test and in l using unpaired two-tailed Student’s t-test. Source data are provided in the Source Data file.