Engineered Microvascular Model of the Blood-Brain-Tumor Barrier Reveals Endothelial Remodeling in Diffuse Midline Glioma.

Diffuse midline glioma (DMG) is a highly aggressive pediatric brain tumor that is difficult to treat because the blood-brain-tumor barrier (BBTB) prevents most drugs from reaching the tumor. A major obstacle for understanding this tumor-vascular niche is the lack of a perfusable vascular model of DMG. To address this, we have established an in vitro model of the DMG-BBTB, comprised of patient-derived DMG tumor cells and primary human brain microvascular endothelial cells, astrocytes, and vascular pericytes, embedded in a fibrin matrix within a microfluidic chip. We report the development and characterization of self-assembled microvascular networks, with consistent vasculature development across a range of tumor cell densities. Perfusion studies showed no significant alterations in vascular permeability when tumor cells were present. To elucidate transcriptomic changes, we employed scRNAseq on devices containing blood-brain barrier (BBB), DMG-BBTB, or tumor necrosis factor alpha (TNFα)-stimulated control. We observed significant differential gene expression between BBB and DMG-BBTB, distinct from inflammatory signatures seen with TNFα perturbation. Our analysis indicated that DMG cells adopted a mesenchymal-like phenotype, with further in silico studies predicting significant receptor-ligand crosstalk between these cells and endothelium. In summary, we developed a high-fidelity DMG-BBTB model that recapitulates transcriptomic features of patient DMG microvasculature and features perfusable vasculature.