Spatial architecture of high-grade glioma reveals tumor heterogeneity within distinct domains.

Background: High-grade gliomas (HGGs) are aggressive primary brain cancers with poor response to standard regimens, driven by immense heterogeneity. In isocitrate dehydrogenase (IDH) wild-type HGG (glioblastoma, GBM), increased intratumoral heterogeneity is associated with more aggressive disease. Methods: Spatial technologies can dissect complex heterogeneity within the tumor ecosystem by preserving cellular organization in situ. We employed GeoMx digital spatial profiling, CosMx spatial molecular imaging, Xenium in situ mapping and Visium spatial gene expression in experimental and validation patient cohorts to interrogate the transcriptional landscape in HGG. Results: Here, we construct a high-resolution molecular map of heterogeneity in GBM and IDH-mutant patient samples to investigate the cellular communities that compose HGG. We uncovered striking diversity in the tumor landscape and degree of spatial heterogeneity within the cellular composition of the tumors. The immune distribution was diverse between samples, however, consistently correlated spatially with distinct tumor cell phenotypes, validated across tumor cohorts. Reconstructing the tumor architecture revealed two distinct niches, one composed of tumor cells that most closely resemble normal glial cells, associated with microglia, and the other niche populated by monocytes and mesenchymal tumor cells. Conclusions: This primary study reveals high levels of intratumoral heterogeneity in HGGs, associated with a diverse immune landscape within spatially localized regions.

Flow Cytometry Identification of Cell Compartments in the Murine Brain.

Glioma can be modelled in the murine brain through the induction of genetically engineered mouse models or intracranial transplantation. Gliomas (oligodendroglioma and astrocytoma) are thought to arise from neuronal and glial progenitor populations in the brain and are poorly infiltrated by immune cells. An improved understanding of oligodendrocytes, astrocytes, and the immune environment throughout tumor development will enhance the analysis and development of brain cancer models. Here, we describe the isolation and analysis of murine brain cell types using a combination of flow cytometry and quantitative RT-PCR strategies to analyze these individual cell populations in vivo.

Human prefrontal cortex gene regulatory dynamics from gestation to adulthood at single-cell resolution.

Human brain development is underpinned by cellular and molecular reconfigurations continuing into the third decade of life. To reveal cell dynamics orchestrating neural maturation, we profiled human prefrontal cortex gene expression and chromatin accessibility at single-cell resolution from gestation to adulthood. Integrative analyses define the dynamic trajectories of each cell type, revealing major gene expression reconfiguration at the prenatal-to-postnatal transition in all cell types followed by continuous reconfiguration into adulthood and identifying regulatory networks guiding cellular developmental programs, states, and functions. We uncover links between expression dynamics and developmental milestones, characterize the diverse timing of when cells acquire adult-like states, and identify molecular convergence from distinct developmental origins. We further reveal cellular dynamics and their regulators implicated in neurological disorders. Finally, using this reference, we benchmark cell identities and maturation states in organoid models. Together, this captures the dynamic regulatory landscape of human cortical development.