Wt1+ stroma programs the transcriptional landscape of large cavity macrophages. (A) Frequency of GATA6+ LCMs in co-culture assay with conditions or treatments as noted. n denotes number of experiments. (B) Heatmap of peritoneal LCM hallmark genes expression in co-cultures. Significant genes exhibited FDR ≤ 0.05, Log2 FC ≥ 2 and were expressed ≥ 1 TPM in all three ex vivo peritoneal macrophage samples. Genes in black are dependent on GATA6-expression; genes in purple are regulated independently of GATA6. (C) Overlap of LCM genes regulated by Wt1+ stromal cells in vitro compared to hallmark LCM genes (Supplemental Table 1). (A) GATA6+ is determined by frequency positive minus isotype positive. (A-B) Co-culture with cell contact (C:C), co-culture with 0.4uM transwell membrane separation (TW), all trans retinoic acid (ATRA), or BMS493. Cells were cultured for 4–6 days at a ratio of 2–11:1 (Peritoneal lavage:Wt1+ stromal cells) for 5 – 6 days. **p<0.005, ***p<0.0005, as determined one-way ANOVA with Dunnett’s multiple comparison post-test (A) or hypergeometric test (C). Mean values or mean values + SEM (A) are shown.