Fig 2: Long-Term Anti-tumor Effects of Trained Granulopoiesis(A) WT mice were treated with ß-glucan or PBS, and after 28 days were subcutaneously inoculated with B16-F10 melanoma cells. Tumor volume was monitored for another 14 days after tumor inoculation (n = 5 mice in the PBS group; n = 6 mice in the ß-glucan group).(B–D) As indicated in the experimental scheme (B), WT CD45.1+ mice were injected with ß-glucan or PBS, and after 7 days BM cells were isolated and were transplanted into CD45.2+ mice. Six weeks after transplantation, recipient mice were inoculated with tumors. In (C), (left) tumor volume and (right) the weight of B16-F10 melanoma tumors at the end of the experiment are shown (n = 6 mice per group). Shown in (D), 14 days after the tumor injection in recipient mice, TANs (CD45+CD11c-CD11b+Ly6c-Ly6g+) were sorted and relative mRNA expression of the “trained TAN1-like signature” was performed. Relative mRNA expression was normalized against 18S rRNA and was set as 1 in TANs from recipients that were transplanted with cells from PBS-treated donor mice (n = 4 mice per group).Data are presented as mean ± SEM; n.s.. non-significant; *p < 0.05, **p < 0.01, ***p < 0.001.See also Figure S3.

Fig 3: Effect of ethanol consumption on macrophage and neutrophil numbers in the lung following infection. (A) Flow cytometry gating strategy to identify neutrophils, alveolar macrophages, and infiltrating macrophages in lung homogenates. (B) Average number of pulmonary cell subsets in lung homogenate at 24 hours post-infection. (C) RNA from lung homogenates was isolated at 24 hours post-infection and cDNA was analyzed by quantitative PCR for expression of Ly6g; target gene expression is normalized to gapdh and presented as fold change to vehicle-treated uninfected mice. Data are presented as mean ± SEM. n = 3-6 mice per group per experiment and data are combined from 2 individual experiments. *p < 0.05 compared to all other groups by one-way ANOVA.

Fig 4: gp130/STAT3 signaling and MDSCs in colitis.WHAT IS CURRENT KNOWLEDGE Myeloid derived suppressor cells (MDSCs) are a heterogeneous group of immature cells that includes precursors of macrophages, granulocytes, dendritic cells and myeloid cells at earlier stages of differentiation. They are defined by their co-expression of Gr-1 and CD11b. MDSCs regulate immune responses and tissue repair in healthy individuals and MDSCs rapidly expands during inflammation, infection and cancer. It is predominantly (70-90%) the granulocytic subset of MDSCs (G-MDSC) that expands, which has a CD11b+Ly6G+Ly6Clow phenotype. G-MDSCs have increased activity of signal transducer and activator of transcription 3 (STAT3), which is activated by binding of cytokines to the glycoprotein (gp)130 receptor and regulates the expansion and survival of G-MDSC subsets. Activation of G-MDSCs leads to the upregulation of arginase 1 (ARG1), which causes the suppression of T cell responses, and to the increased production of other suppressive cytokines, such as interleukin (IL-)10 and transforming growth factor-ß (TGF-ß). WHAT IS NEW HERE gp130757F/F mice with a phenylalanine (F) for tyrosine (Y) substitution at the 757 residue of the gp130 receptor show sustained STAT3 signalling due to the inhibition of negative feedback loops, which normally activate alternative signalling pathways downstream of gp130. Experimental colitis, induced with 3% dextran sulphate sodium (DSS) in drinking water in gp130757F/F mice and compared to water (H2O)-treated gp130757F/F and wildtype (gp130757Y/Y) mice, resulted in reduced disease severity and amelioration of intestinal inflammation with expansion of G-MDSCs in the colon, increased arginase 1 expression and activity and increased expression of the protective cytokines IL-19 and IL-33 in the colon. LysMcre/Stat3flox mice with myeloid-specific STAT3 deficiency, were not protected from DSS-induced colitis and colons showed reduced numbers of G-MDSCs, increased gene expression of pro-inflammatory interferon ? (IFN?) and inducible nitric oxide synthase (iNos), and decreased expression of IL-19 and IL-33. Additionally, G-MDSCs of LysMcre/Stat3flox mice produced significantly less anti-inflammatory cytokines, such as IL-4, IL-10 and IL-13, compared to gp130757Y/Y mice. We suggest that the resistance to DSS-induced colitis in gp130757F/F mice is via myeloid-cell specific STAT3 activation, MDSC expansion in the colon and increased production of suppressive and protective cytokines.

Fig 5: TLR Activation Induces Spic in Monocytes and Macrophages(A–C) LPS (50 µg) or PBS (control) was injected intraperitoneally (i.p.) into mice of indicated genotypes (headers). Peripheral blood was collected 3 days later. Shown are the flow cytometry plots (FCSs) with indicated markers. (A) Cells pre-gated for CD45+ singlets expresses SPIC (GFP+) selectively in CD11B+ myeloid cells. (B) Expression of indicated markers on cells gated on SPIC expression (A, arrow). (C) FCS showing SPIC expression in monocyte subsets defined by Ly6C (pre-gated for CD45+ singlets).(D) FCS of circulating monocytes (CD45+LY6G-CD115+) from mice of indicated genotypes (header) showing Spic expression in circulating leukocytes.(E) Zbtb46GFP/GFP bone marrow cells were cultured in GM-CSF for 7 days. F4/80hiZbtb46GFP- macrophages (MAC) and F4/80loZbtb46GFP+ DCs were purified by fluorescence-assisted cell sorting (FACS), cultured in media without cytokines, and treated with LPS. Cells were harvested 24 h later, and qRT-PCR was performed for indicated genes (y axis, normalized to 18S rRNA). MACs but not DCs induced Spic while both cell types increased Tnfa expression with LPS.FCS, numbers represent percentage of cells within indicated gate. (A–D) Represents =3 experiments with =3 mice per group. qRT-PCR, data representative of =3 independent experiments; and graphs show a single experiment with n =2 per group. Results are expressed as mean ± SEM. p = 0.05 (*), p = 0.01 (**), p = 0.001 (***), and p = 0.0001 (****). See also Figure S1.