Fig. 3

GPNMB-KO mice display a higher density and soma size of microglia and accumulate pro-inflammatory TAMs. A Representative staining of IBA1 (left) and merge with DAPI (right; IBA1 = green, DAPI = blue) of brain slices from naïve WT (n = 3) and KO (n = 3). Scale bar represents 100 µm. The inserts show an expanded magnification of an individual microglia. B IBA1⁺ cell density normalized to DAPI in % and C soma volume (in µm³) as obtained from slices as shown in A. Statistical analysis was respectively performed using unpaired t-test. D Representative stainings of IBA1 (left) and merge with DAPI (right; IBA1 = green, DAPI = blue) of brain slices from tumor-bearing WT (n = 7) and KO (n = 7) in three different brain regions. Ipsilateral: Outside of the tumor in the ipsilateral hemisphere. Invasive edge (IE): Border region from tumor to non-tumor brain tissue, defined by the RFP signal and DAPI density. Core: Core tumor tissue area. Scale bar represents 40 µm. The inserts show an expanded magnification of an individual microglia. The bar graph on the right summarizes the percentage of IBA1⁺ cells normalized to the DAPI⁺ cells for these three tissue regions. Statistical analysis was performed using 2-way ANOVA with Sidak´s multiple comparisons test. E Representative staining of MHCII (left), IBA1 (middle) and merge with DAPI (right; MHCII = green, IBA1 = red, DAPI = blue) of brain slices from tumor-bearing WT (n = 7) and KO (n = 6). Scale bar represents 50 µm. Statistical analysis was performed using an unpaired t-test. Error bars represent SD. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001