Fig 2: Res promoted the polarization of microglia to M2 type and play an anti-inflammatory role. (A) Protein levels of Arg-1 in microglia in the hippocampal CA1 region; (B) protein levels of iNOS in microglia in the hippocampal CA1 region; (C) percentage of iNOS+DAPI+/Iba-1+DAPI+ and Arg-1+DAPI+/Iba-1+DAPI+; (D) percentage of Iba-1+DAPI+/DAPI+; (E) fluorescent labeling of M1 and M2 microglia; (F) the levels of IL-1ß, IL-4, IL-10 and TNF-a in hippocampus (pg/mL) in different groups were detected. *P<0.05 indicated vs Con group; #P<0.05 indicated vs PTX group; &P<0.05 indicated vs PTX+Res group; $P<0.05 indicated vs PTX group; ns indicated no statistical significance. Scale bar = 50 µm.

Fig 3: NLRP3 depletion in microglia reduces phagocytosis potential and release of pro-inflammatory cytokines. (A) Phagocytosis for zymosan was assessed in sorted disc microglia from mice with microglia-specific alteration in NLRP3 expression. (B) ELISA for IL-1ß, TNFa, IFN?, ARG1 and CD163 in sorted disc microglia from mice with microglia-specific alteration in NLRP3 expression. The relative levels to those from NLRP3mut (=1) were shown. *p<0.05. ns, non-significant.

Fig 4: Arginase 1 gene and protein expression in the whole tumour and single cells. This figure shows that arginase mRNA and protein were expressed at much higher levels in metastatic than non-metastatic tumours. A Arg1 mRNA levels in 67NR (N = 5) and 66cl4 (N = 5) tumours were measured using qRT-PCR. B Immunoblots of the ARG1 protein and ERK1/2 (loading control) in 67NR (N = 6) and 66cl4 (N = 6) tumours. C–F Representative images of in situ hybridization (C, D) and immunohistochemistry (E, F) showing the spatial distribution of Arg1 mRNA and ARG1 protein in 67NR and 66cl4 tumours. The panels show representative images at 100X magnification, and the inset shows images at 400X magnification. G–I Arg1 mRNA and ARG1 protein levels were significantly higher in CD45+ immune cells than in CD45− non-immune cells from 66cl4 tumours than in CD45+ and CD45− cells from 67NR tumours. G Arg1 mRNA level in CD45+ and CD45− from 67NR (N = 4) and 66cl4 (N = 4) tumours. H Representative flow cytometry plots showing CD45 vs ARG1 protein in single cells from 66cl4 and 67NR tumours. I Percentage of ARG1 positive CD45+ and CD45− cells in 67NR (N = 7) and 66cl4 (N = 8) tumours. Values are presented as mean ± SEM and each data point represents a single animal. Statistical significance was determined using the Mann–Whitney test (*p < 0.05, **p < 0.005)

Fig 5: ARG1 activity in tumours and plasma. A–C Graphical representation of arginine (A) and ornithine (B) levels in tumour in µmol/mg of tissue, as measured by mass spectrometry. (C) The ratio of arginine to ornithine. Bars represent the mean ± SEM, and each data point represents a single tumour (67NR N = 10, 66cl4 N = 11). Statistical significance was determined using the Mann–Whitney test. *p < 0.05, **p < 0.005, ***p < 0.0005. D–F show the levels of arginine (D) and ornithine (E) in µM in plasma, while (F) shows the ratio of arginine to ornithine in plasma. Bars represent mean ± SEM and each data point represents a single animal (control N = 12, 67NR N = 12, 66cl4 N = 12). Statistical significance was determined using the Mann–Whitney test. *p < 0.05, **p < 0.005, ***p < 0.0005