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 <i>in vivo</i> 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.