Long-Term Effects of Radiation Therapy on Cerebral Microvessel Proteome: A Six Month Post-Exposure Analysis

Radiation therapy (RT) treats primary and metastatic
brain tumors,
with about one million Americans surviving beyond six months post-treatment.
However, up to 90% of these survivors develop RT-induced cognitive
impairment. Emerging evidence links cognitive decline to RT-induced
endothelial dysfunction in brain microvessels, yet in vivo studies remain limited. Investigating the molecular and cellular
pathways connecting RT, endothelial injury, and cognitive impairment
is vital for developing targeted interventions. We performed quantitative
proteomic analysis of cerebral microvessels from five control and
five irradiated mice (12 Gy) 6 months post-RT. Bioinformatics tools,
including gene ontology (GO) enrichment, Mitocarta analysis, Ingenuity
Pathway Analysis (IPA), and iPathwayGuide, identified affected pathways.
Findings were validated by Western blotting. RT significantly altered
414 proteins, with 157 upregulated and 257 downregulated. GO analysis
indicated metabolic pathway disruptions, and Mitocarta analysis revealed
a significant presence of mitochondrial proteins among the dysregulated
proteins. IPA identified 76 enriched canonical pathways, 34 transcription
regulators, 6 nuclear receptors, and 5 growth factors involved in
RT-induced damage responses. IPA predicted mitochondrial dysfunction
in the irradiated group, confirmed by Western blotting. Significant
proteomic changes in cerebral microvessels suggest RT-induced metabolic
dysfunction in cerebral microvasculature, including oxidative phosphorylation,
the TCA cycle, and glycolysis.