Integrated Transcriptomic Analysis Reveals Coordinated Gliovascular Remodeling Across Diffuse Glioma Grades.

Background

The gliovascular unit forms the structural and functional basis of the glymphatic system, which facilitates cerebrospinal fluid-interstitial fluid exchange to maintain brain homeostasis. Although disruption of individual astrocytic, vascular, and extracellular matrix (ECM) components has been described in diffuse glioma, it remains unknown whether these alterations represent isolated pathological events or a coordinated remodeling program across glioma grades.

Methods

Bulk transcriptomic signatures representing eight components of the gliovascular unit were quantified in The Cancer Genome Atlas (TCGA) and independently validated in the Chinese Glioma Genome Atlas (CGGA). Pathway activity was compared across WHO grades and IDH status, followed by gene-level, network, and grade-specific analyses to characterize the grade-associated patterns of gliovascular remodeling. Laser-capture microdissected RNA sequencing data from the Ivy Glioblastoma Atlas Project was subsequently used to define the anatomical distribution of representative gliovascular markers within glioblastoma (GBM). Finally, multivariable Cox proportional hazards regression was performed to evaluate associations between gliovascular pathway activity and overall survival.

Results

Diffuse glioma was characterized by coordinated grade-associated remodeling of the gliovascular unit across independent patient cohorts. Lower-grade tumors were characterized by greater expression of homeostatic astrocyte- and endfoot-associated transcriptional programs, whereas higher-grade tumors showed increasing inflammatory, ECM-remodeling, basement membrane-remodeling, and angiogenic signatures. Regional analysis demonstrated corresponding anatomical compartmentalization of these transcriptional features within GBM. Despite closely reflecting glioma grade, gliovascular remodeling was not independently associated with overall survival.

Conclusions

Coordinated grade-associated remodeling of the gliovascular unit provides a unifying framework linking astrocyte-associated, inflammatory, and vascular remodeling transcriptional programs across glioma grades. This systems-level model establishes a foundation for future mechanistic studies examining how disruption of gliovascular homeostasis contributes to glymphatic dysfunction, sleep disturbance, and disease progression.