Fig. 6: Ferrichrome polarizes macrophages to an M1-like phenotype via down-regulation of ferroportin in a TLR4-dependent manner.
From: Reprogramming of pancreatic adenocarcinoma immunosurveillance by a microbial probiotic siderophore
a Schematic representation of ferrichrome treatment regimen of UN-KPC-960 tumor-bearing WT and TLR4−/− mice. b Flow cytometry analysis of (c) total splenic macrophage content,(d) MHCIIhi (M1-like) and (e) MHClo (M2-like) splenic macrophage frequencies in WT and TLR4−/− mice treated with ferrichrome (blue) or vehicle control (black) (n = 3–4 mice per treatment group). f qPCR analysis of M1 and M2 markers in peritoneal macrophages isolated from wild-type or TLR4 knockout mice and treated with IL-4 alone (20 ng/mL) or ferrichrome + IL-4 for 24 h (n = 2–3). g PCR analysis of M1 markers in RAW264.7 cells treated with vehicle, ferrichrome, or ferrichrome + CLI-095 (TLR4 inhibitor) for 24 h. h qPCR analysis of Fpn and hepcidin mRNA levels in RAW264.7 cells pre-treated with CLI-095 in the presence or absence of ferrichrome for 24 h. Graphs are representative of at least two independent experiments with similar results. i Representative image and quantification of dual immunostaining of tumors treated with ferrichrome or vehicle for the macrophage marker F4/80 (green) and Fpn (red). Quantification was evaluated using ImageJ (n = 3 mice). Bar on micrographs indicates 50 µm. Mean ± SEM shown. **p < 0.01, and ***p < 0.001 as determined by Student’s t test.
