Long-Term Effects of Radiation Therapy on Cerebral Microvessel Proteome: A Six-Month Post-Exposure Analysis
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Background
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 survivors experience RT-induced cognitive impairment. Emerging evidence links cognitive decline to RT-induced endothelial dysfunction in brain microvessels, yet in vivo studies of endothelial injury remain limited. Investigating the molecular and cellular pathways connecting RT, endothelial dysfunction, and cognitive impairment is vital for developing targeted interventions. This study examines proteomic changes in cerebral microvessels following RT.
Methods
We conducted a comprehensive quantitative analysis comparing the proteome in cerebral microvessels from five control mice and five irradiated mice (12 Gy) 6 months after RT. Bioinformatics analyses included gene ontology (GO) enrichment, Mitocarta analysis, Ingenuity Pathway Analysis (IPA), and iPathwayGuide. Predictions from the analyses were validated by western blotting.
Results
Our data identified significant dysregulation of 414 proteins following RT, with 157 upregulated and 257 downregulated. Gene ontology analysis indicated that the majority of the dysregulated proteins were part of various metabolic pathways. Cross referencing with Mitocarta revealed a significant presence of mitochondrial proteins among the dysregulated proteins, indicating potential mitochondrial metabolic dysfunction. Further investigation with IPA analysis uncovered 76 enriched canonical pathways, 34 transcription regulators, 6 nuclear receptors, and 5 growth factors involved in RT-induced damage responses in cerebral microvessels. IPA canonical pathway analysis predicted mitochondrial dysfunction due to inhibition of various metabolic pathways in the irradiated group. Validation with western blotting confirmed the bioinformatics predictions from the proteomic dataset.
Conclusions
Our data show significant proteomic changes in cerebral microvessels 6 months post-radiation, including oxidative phosphorylation, the TCA cycle, and glycolysis, suggesting metabolic mechanisms of RT-induced microvascular dysfunction.
