Fig. 2: Collagen-mediated immune suppression is present within meningiomas.

A Multiprotein immunofluorescence demonstrates that Phago.TAM cells in meningiomas express immunosuppressive proteins such as TIM-3 (left, yellow label) and LAIR-1 (right, white label). Representative results are shown; n = 4 patient samples were tested from varying WHO grades with similar findings. Scale bar is 100 µM and 20 µM for the inset. B Using the same n = 4 patient samples, collagens were strongly detected in meningioma stromal regions and exhibited concentric laminar patterns (left). Both tumor and stromal areas harbor cells expressing immune suppressive LAIR-1 - a known receptor for collagens (right). The right image shows an overlapping region from panel A. Scale bar is 200 (left) and 100 (right) µM. C Volcano plot showing select chemokines enriched in the dura (left side) and meningioma tissues (right side) based on scRNA-seq of immune clusters shown in Fig. 1A. The annotated chemokines correlate with the elevated myeloid (blue text) and lymphoid (red text) populations in the meningioma and dura, respectively. Differentially expressed genes were calculated through pseudobulk analysis using DESeq2 analysis (two-sided Wald test with Benjamini-Hochberg (BH) procedure for multiple correction) on immune cells grouped to compare between dura and meningioma. D UMAP plot of scRNA-seq data from meningiomas and dura reveals three distinctive NK populations associated with resting (green), activated (blue), and exhausted (red) phenotypes. Cell annotation was performed based on DEGs using Seurat FindAllMarkers. E Dot plot of selected NK marker genes. Bubble size corresponds to the percent of cells expressing each marker; colors indicate average expression. Activated NK cells exhibited higher levels of granzyme and CD247, which were relatively absent in resting populations. Exhausted NK cells had high expression of both activation and inhibition markers and components of the TGF-β pathway.