Fig. 7: IL-9 impacts lung macrophage function by regulating Arg1 expression.

a Heatmap showing Arg1 expression from RNA-Seq experiment described in Fig. 5. b, c Arg1 expression in macrophages from B16 tumor model (b) (n = 9 mice for WT group, n = 7 mice for Il9r^−/− group) and orthotopic LLC lung tumor model (c) (n = 6 mice for WT group, n = 5 mice for Il9r^−/− group). d Arg1 expression in mixed bone marrow chimeric mice described in Fig. 4f (n = 9 mice). e CD11c⁻IM and CD11c⁺IM were isolated from WT tumor bearing mice and stimulated with PBS or 40 ng/ml IL-9 for 48 h. Arg1 production was analyzed by flow. f Arginase activity were analyzed in total lung macrophages and tumor foci (n = 5 mice for WT and Il9r^−/− - B16-Lung Mac group, n = 5 mice for WT-LLC group, n = 12 mice for Il9r^−/− -LLC−Lung Mac, n = 7 mice for WT- orthotopic LLC tumor group, n = 2 mice for Il9r^−/−- orthotopic LLC tumor group). g–i YARG mice were injected with B16 cells, and total lung Arg1^+/− macrophages were sorted from intact lungs of tumor bearing mice on day 14. Cells were intravenously injected into Il9r^−/− mice 4 days after tumor injection. f, g Tumor development was analyzed on day 23. h Donor macrophages were analyzed by flow cytometry (n = 2 mice for WT group, n = 8 mice for Il9r^−/− + PBS group, n = 12 mice for Il9r^−/− + YFP⁺ Mac group, n = 14 mice for Il9r^−/− +YFP^- Mac group). i Lung Arg1⁺ macrophages were analyzed by flow cytometry (n = 2 mice for WT group, n = 8 mice for Il9r^−/− + PBS group, n = 10 mice for Il9r^−/− + YFP⁺ Mac group, n = 13 mice for Il9r^−/− +YFP⁻ Mac group). Mac: macrophage. j Arg1^fl/fl LysM-Cre^+/- mice were injected with B16 tumor, tumor development was analyzed on day 14 and day 21 (n = 13 mice for D14 Arg1^fl/fl LysM-Cre⁺ group, n = 6 mice for D21 Arg1^fl/fl LysM-Cre⁺ group, n = 9 mice for D14 and D21 Arg1^fl/fl LysM-Cre^- groups). k IMs from tumor-bearing Arg1^fl/fl LysM-Cre⁺ mice or littermate control mice were sorted from intact lungs of tumor bearing mice 14 days after tumor injection and transferred to Il9r^−/− mice which have been injected with tumor 4 days before. Tumor development was analyzed on day 17 (n = 6 mice for Arg1^fl/fl LysM-Cre^- group, n = 5 mice for Arg1^fl/fl LysM-Cre⁺ group). l Arg1⁺ cells were analyzed from WT tumor bearing mice by flow cytometry (n = 8 mice per group). m Dot plot showing ARG1 expression in different clusters from human lung cancer patient scRNA-Seq. Data are the mean ± SEM. Unpaired two-tailed Student t-test was used for comparison in b, c, f and k. Two-tailed paired t test was used for generating p value in d. One-way ANOVA with a Dunnett’s multiple comparison test was used for multiple comparisons in h and i. Two-way ANOVA with Sidak’s multiple comparisons was used for comparisons in j.