Fig. 2

GBM and microglia interplay leading to glutamate upregulation. a Schematic representation of GBM and microglia interplay. b, c Microglial phenotypes in the GBM-microglia assembloid assessed by immunostaining with CD86 (M1) and CD206 (M2) markers. Scale bar represents 200 μm. d Cytokine profiles of GBM and microglia. GBM-derived cytokines, GM-CSF inducing microglial polarization to M1 phenotype and IL-6 and G-CSF to M2 phenotype were detected (n = 2). e Increase of glutamate level mediated by GBM-microglia interplay. Adding neutralizing antibodies targeting GM-CSF (aGM-CSF), IL-6 (aIL-6), and G-CSF (aG-CSF) in the GBM conditional media decreased glutamate level released from microglia. # indicates microglia single culture treated with GBM conditional media. Quantitative data were presented as means ± SD (n = 3, unless otherwise noted). *, p < 0.05; **, p < 0.01; ***, p < 0.001; ****, p < 0.0001. p values were calculated by two-tailed unpaired Student's t-test for comparisons between two groups, and by one-way ANOVA for multiple comparisons. GBM, glioblastoma; MG, microglia