Figure 5.

COMT-deficient glioma remodels the TIME and promotes microglial proliferation and activation. A, UMAP visualization of tumor-infiltrated CD45⁺ cells identified by FlowSOM clustering. Tumor samples collected from brain were multiplexed, pooled, and downsampled to 2,000 live CD45⁺ cells per sample for scRNA-seq. Cells from control tumors were collected on day 12 post intracranial tumor implantation (n = 6) while cells from Comt-KO tumors were collected on day 12 (n = 3) and day 25 (n = 3), respectively. Rep TAM, replicating tumor-associated macrophage; B, B lymphocyte; NK, natural killer; CD4 T, CD4⁺ T cells; CD8 T, CD8⁺ T cells; CCR7 DC, CCR7⁺ dendritic cells; cDC, conventional dendritic cells; PMN, polymorphonuclear neutrophil. B, Dot plot of cell-specific marker gene expression in different cell clusters. C and D, Contour plot (C) and bar graph (D) comparing cellular densities per cluster in VC and Comt-KO glioma tumors. In D, each dot represents one mouse sample. E and F, Identification (E) and quantification (F) of microglia (MG) and TAM in VC and Comt-KO CT2A tumors (n = 3) by flow cytometry. G, UMAP plot showing the heterogeneity of myeloid cells at higher resolution. H, Quantification of cell density per subcluster in VC and Comt-KO CT2A tumors. I and J, Identification (I) of homeostatic (MG0) and DAM subclusters using gene module analysis. Violin plots (J) indicating expression of individual marker genes used in gene module analysis. Red, homeostatic microglia (MG0); green, DAM. K, Immunohistochemical staining of VC and Comt-KO CT2A brain tumor tissues with IBA1 (red), CD68 (green), and DAPI (blue). DAPI was used to mark the nuclei. Scale bar, 50 μm. Error bars, mean ± SEM. *, P < 0.05; **, P < 0.01; ***, P < 0.001;****, P < 0.0001. P < 0.05 was considered statistically significant. ns, not significant.