Glial Cells May Shape Brain Tumor Microenvironments

Alex Moir ’23

Figure 1: A head MRI of a patient with a glioma 

Glial cells, located in the central nervous system (CNS), support neurons by clearing extracellular waste and mounting an immune response against potential pathogens. Glioma are tumors occurring in the CNS that originate from these glial cells. As glioma tumors progress and become more aggressive, they invade surrounding tissue and develop a hospitable tumor microenvironment (TME). Two types of resident CNS immune cells, microglia, and macrophages are recruited by gliomas to help modulate inflammation in the TME. Stony Brook researcher Dr. Tsirka and her team hypothesized that glioma-associated microglia and macrophages (GAMs) may exist in subpopulations within the TME, playing distinct roles depending on their location in the tumor. In order to determine whether this is true, the team investigated peritumoral GAMs (PGAMs), the GAMs on the edge of glioma tumors. 

The team first sampled tissue from the edge of various human patient gliomas. Using single-cell RNA sequencing, they identified populations of cells expressing microglia and macrophage associated protein markers in each region. This technique allowed for the isolation of region-specific PGAMs and subsequent analysis of their genomes.  The researchers found that PGAMs were particularly enriched for pro-inflammatory cell signaling molecules and receptors, which implies that PGAMs have important differences in the genes they express compared to other GAM populations. Additionally, certain expressed receptors indicated that PGAMs can interact with proteins found on the surface of cells deeper inside the tumor. This interaction suggests that PGAMs may act to facilitate communication between the tissue outside the TME and the cells inside the TME.

The team’s findings provide a better understanding of how gliomas are able to organize and manipulate their environment to promote growth and evade the immune system. Their findings may also help provide new targets for the development of glioma therapies through disruption and targeting of region-specific GAMs and their unique functions. Future research may involve a deeper investigation of GAM populations and their functions.  

Works Cited: 

[1] M. Caponegro,  et al., A distinct microglial subset at the tumor-stroma interface of glioma. Glia 69, 1-15 (2021). doi: /10.1002/glia.23991.

[2] Image retrieved from: https://pixabay.com/illustrations/mri-magnetic-resonance-roentgen-782457/ 

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